Revision 9cf85473209ea8ae2b56c13145c4704d12ee1374 authored by Filip Hejsek on 28 January 2024, 04:09:17 UTC, committed by Johannes Schindelin on 17 April 2024, 20:30:01 UTC
While it is expected to have several git dirs within the `.git/modules/`
tree, it is important that they do not interfere with each other. For
example, if one submodule was called "captain" and another submodule
"captain/hooks", their respective git dirs would clash, as they would be
located in `.git/modules/captain/` and `.git/modules/captain/hooks/`,
respectively, i.e. the latter's files could clash with the actual Git
hooks of the former.

To prevent these clashes, and in particular to prevent hooks from being
written and then executed as part of a recursive clone, we introduced
checks as part of the fix for CVE-2019-1387 in a8dee3ca61 (Disallow
dubiously-nested submodule git directories, 2019-10-01).

It is currently possible to bypass the check for clashing submodule
git dirs in two ways:

1. parallel cloning
2. checkout --recurse-submodules

Let's check not only before, but also after parallel cloning (and before
checking out the submodule), that the git dir is not clashing with
another one, otherwise fail. This addresses the parallel cloning issue.

As to the parallel checkout issue: It requires quite a few manual steps
to create clashing git dirs because Git itself would refuse to
initialize the inner one, as demonstrated by the test case.

Nevertheless, let's teach the recursive checkout (namely, the
`submodule_move_head()` function that is used by the recursive checkout)
to be careful to verify that it does not use a clashing git dir, and if
it does, disable it (by deleting the `HEAD` file so that subsequent Git
calls won't recognize it as a git dir anymore).

Note: The parallel cloning test case contains a `cat err` that proved to
be highly useful when analyzing the racy nature of the operation (the
operation can fail with three different error messages, depending on
timing), and was left on purpose to ease future debugging should the
need arise.

Signed-off-by: Filip Hejsek <filip.hejsek@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
1 parent b20c10f
Raw File
configure.ac
#                                               -*- Autoconf -*-
# Process this file with autoconf to produce a configure script.

## Definitions of private macros.

# GIT_CONF_SUBST(VAL, VAR)
# ------------------------
# Cause the line "VAR=VAL" to be eventually appended to ${config_file}.
AC_DEFUN([GIT_CONF_SUBST],
[AC_REQUIRE([GIT_CONF_SUBST_INIT])
config_appended_defs="$config_appended_defs${newline}dnl
$1=m4_if([$#],[1],[${$1}],[$2])"])

# GIT_CONF_SUBST_INIT
# -------------------
# Prepare shell variables and autoconf machine required by later calls
# to GIT_CONF_SUBST.
AC_DEFUN([GIT_CONF_SUBST_INIT],
    [config_appended_defs=; newline='
'
    AC_CONFIG_COMMANDS([$config_file],
                       [echo "$config_appended_defs" >> "$config_file"],
                       [config_file=$config_file
                        config_appended_defs="$config_appended_defs"])])

# GIT_ARG_SET_PATH(PROGRAM)
# -------------------------
# Provide --with-PROGRAM=PATH option to set PATH to PROGRAM
# Optional second argument allows setting NO_PROGRAM=YesPlease if
# --without-PROGRAM version used.
AC_DEFUN([GIT_ARG_SET_PATH],
    [AC_ARG_WITH([$1],
        [AS_HELP_STRING([--with-$1=PATH],
                        [provide PATH to $1])],
        [GIT_CONF_APPEND_PATH([$1], [$2])],
        [])])

# GIT_CONF_APPEND_PATH(PROGRAM)
# -----------------------------
# Parse --with-PROGRAM=PATH option to set PROGRAM_PATH=PATH
# Used by GIT_ARG_SET_PATH(PROGRAM)
# Optional second argument allows setting NO_PROGRAM=YesPlease if
# --without-PROGRAM is used.
AC_DEFUN([GIT_CONF_APPEND_PATH],
    [m4_pushdef([GIT_UC_PROGRAM], m4_toupper([$1]))dnl
    if test "$withval" = "no"; then
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		GIT_UC_PROGRAM[]_PATH=$withval
		AC_MSG_NOTICE([Disabling use of GIT_UC_PROGRAM])
		GIT_CONF_SUBST([NO_]GIT_UC_PROGRAM, [YesPlease])
		GIT_CONF_SUBST(GIT_UC_PROGRAM[]_PATH, [])
	else
		AC_MSG_ERROR([You cannot use git without $1])
	fi
    else
	if test "$withval" = "yes"; then
		AC_MSG_WARN([You should provide path for --with-$1=PATH])
	else
		GIT_UC_PROGRAM[]_PATH=$withval
		AC_MSG_NOTICE([Setting GIT_UC_PROGRAM[]_PATH to $withval])
		GIT_CONF_SUBST(GIT_UC_PROGRAM[]_PATH, [$withval])
	fi
    fi
    m4_popdef([GIT_UC_PROGRAM])])

# GIT_PARSE_WITH(PACKAGE)
# -----------------------
# For use in AC_ARG_WITH action-if-found, for packages default ON.
# * Set NO_PACKAGE=YesPlease for --without-PACKAGE
# * Set PACKAGEDIR=PATH for --with-PACKAGE=PATH
# * Unset NO_PACKAGE for --with-PACKAGE without ARG
AC_DEFUN([GIT_PARSE_WITH],
    [m4_pushdef([GIT_UC_PACKAGE], m4_toupper([$1]))dnl
    if test "$withval" = "no"; then
	NO_[]GIT_UC_PACKAGE=YesPlease
    elif test "$withval" = "yes"; then
	NO_[]GIT_UC_PACKAGE=
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	NO_[]GIT_UC_PACKAGE=
	GIT_UC_PACKAGE[]DIR=$withval
	AC_MSG_NOTICE([Setting GIT_UC_PACKAGE[]DIR to $withval])
	GIT_CONF_SUBST(GIT_UC_PACKAGE[DIR], [$withval])
    fi
    m4_popdef([GIT_UC_PACKAGE])])

# GIT_PARSE_WITH_SET_MAKE_VAR(WITHNAME, VAR, HELP_TEXT)
# -----------------------------------------------------
# Set VAR to the value specified by --with-WITHNAME.
# No verification of arguments is performed, but warnings are issued
# if either 'yes' or 'no' is specified.
# HELP_TEXT is presented when --help is called.
# This is a direct way to allow setting variables in the Makefile.
AC_DEFUN([GIT_PARSE_WITH_SET_MAKE_VAR],
[AC_ARG_WITH([$1],
 [AS_HELP_STRING([--with-$1=VALUE], $3)],
 if test -n "$withval"; then
  if test "$withval" = "yes" -o "$withval" = "no"; then
    AC_MSG_WARN([You likely do not want either 'yes' or 'no' as]
		     [a value for $1 ($2).  Maybe you do...?])
  fi
  AC_MSG_NOTICE([Setting $2 to $withval])
  GIT_CONF_SUBST([$2], [$withval])
 fi)])# GIT_PARSE_WITH_SET_MAKE_VAR

#
# GIT_CHECK_FUNC(FUNCTION, IFTRUE, IFFALSE)
# -----------------------------------------
# Similar to AC_CHECK_FUNC, but on systems that do not generate
# warnings for missing prototypes (e.g. FreeBSD when compiling without
# -Wall), it does not work.  By looking for function definition in
# libraries, this problem can be worked around.
AC_DEFUN([GIT_CHECK_FUNC],[AC_CHECK_FUNC([$1],[
  AC_SEARCH_LIBS([$1],,
  [$2],[$3])
],[$3])])

#
# GIT_STASH_FLAGS(BASEPATH_VAR)
# -----------------------------
# Allow for easy stashing of LDFLAGS and CPPFLAGS before running
# tests that may want to take user settings into account.
AC_DEFUN([GIT_STASH_FLAGS],[
if test -n "$1"; then
   old_CPPFLAGS="$CPPFLAGS"
   old_LDFLAGS="$LDFLAGS"
   CPPFLAGS="-I$1/include $CPPFLAGS"
   LDFLAGS="-L$1/$lib $LDFLAGS"
fi
])

dnl
dnl GIT_UNSTASH_FLAGS(BASEPATH_VAR)
dnl -----------------------------
dnl Restore the stashed *FLAGS values.
AC_DEFUN([GIT_UNSTASH_FLAGS],[
if test -n "$1"; then
   CPPFLAGS="$old_CPPFLAGS"
   LDFLAGS="$old_LDFLAGS"
fi
])

## Configure body starts here.

AC_PREREQ(2.59)
AC_INIT([git], [@@GIT_VERSION@@], [git@vger.kernel.org])

AC_CONFIG_SRCDIR([git.c])

config_file=config.mak.autogen
config_in=config.mak.in

GIT_CONF_SUBST([AUTOCONFIGURED], [YesPlease])

# Directories holding "saner" versions of common or POSIX binaries.
AC_ARG_WITH([sane-tool-path],
  [AS_HELP_STRING(
    [--with-sane-tool-path=DIR-1[[:DIR-2...:DIR-n]]],
    [Directories to prepend to PATH in build system and generated scripts])],
  [if test "$withval" = "no"; then
    withval=''
  else
    AC_MSG_NOTICE([Setting SANE_TOOL_PATH to '$withval'])
  fi
  GIT_CONF_SUBST([SANE_TOOL_PATH], [$withval])],
  [# If the "--with-sane-tool-path" option was not given, don't touch
   # SANE_TOOL_PATH here, but let defaults in Makefile take care of it.
   # This should minimize spurious differences in the behaviour of the
   # Git build system when configure is used w.r.t. when it is not.
   :])

## Site configuration related to programs (before tests)
## --with-PACKAGE[=ARG] and --without-PACKAGE
#
# Set lib to alternative name of lib directory (e.g. lib64)
AC_ARG_WITH([lib],
 [AS_HELP_STRING([--with-lib=ARG],
                 [ARG specifies alternative name for lib directory])],
 [if test "$withval" = "no" || test "$withval" = "yes"; then
	AC_MSG_WARN([You should provide name for --with-lib=ARG])
  else
	lib=$withval
	AC_MSG_NOTICE([Setting lib to '$lib'])
	GIT_CONF_SUBST([lib])
  fi])

if test -z "$lib"; then
   AC_MSG_NOTICE([Setting lib to 'lib' (the default)])
   lib=lib
fi

AC_ARG_ENABLE([pthreads],
 [AS_HELP_STRING([--enable-pthreads=FLAGS],
  [FLAGS is the value to pass to the compiler to enable POSIX Threads.]
  [The default if FLAGS is not specified is to try first -pthread]
  [and then -lpthread.]
  [--disable-pthreads will disable threading.])],
[
if test "x$enableval" = "xyes"; then
   AC_MSG_NOTICE([Will try -pthread then -lpthread to enable POSIX Threads])
elif test "x$enableval" != "xno"; then
   PTHREAD_CFLAGS=$enableval
   AC_MSG_NOTICE([Setting '$PTHREAD_CFLAGS' as the FLAGS to enable POSIX Threads])
else
   AC_MSG_NOTICE([POSIX Threads will be disabled.])
   NO_PTHREADS=YesPlease
   USER_NOPTHREAD=1
fi],
[
   AC_MSG_NOTICE([Will try -pthread then -lpthread to enable POSIX Threads.])
])

# Define option to enable JavaScript minification
AC_ARG_ENABLE([jsmin],
[AS_HELP_STRING([--enable-jsmin=PATH],
  [PATH is the name of a JavaScript minifier or the absolute path to one.])],
[
  JSMIN=$enableval;
  AC_MSG_NOTICE([Setting JSMIN to '$JSMIN' to enable JavaScript minifying])
  GIT_CONF_SUBST([JSMIN])
])

# Define option to enable CSS minification
AC_ARG_ENABLE([cssmin],
[AS_HELP_STRING([--enable-cssmin=PATH],
  [PATH is the name of a CSS minifier or the absolute path to one.])],
[
  CSSMIN=$enableval;
  AC_MSG_NOTICE([Setting CSSMIN to '$CSSMIN' to enable CSS minifying])
  GIT_CONF_SUBST([CSSMIN])
])

## Site configuration (override autodetection)
## --with-PACKAGE[=ARG] and --without-PACKAGE
AC_MSG_NOTICE([CHECKS for site configuration])
#
# Define NO_SVN_TESTS if you want to skip time-consuming SVN interoperability
# tests.  These tests take up a significant amount of the total test time
# but are not needed unless you plan to talk to SVN repos.
#
# Define NO_OPENSSL environment variable if you do not have OpenSSL.
#
# Define OPENSSLDIR=/foo/bar if your openssl header and library files are in
# /foo/bar/include and /foo/bar/lib directories.
AC_ARG_WITH(openssl,
AS_HELP_STRING([--with-openssl],[use OpenSSL library (default is YES)])
AS_HELP_STRING([],              [ARG can be prefix for openssl library and headers]),
GIT_PARSE_WITH([openssl]))

# Define USE_LIBPCRE if you have and want to use libpcre. Various
# commands such as log and grep offer runtime options to use
# Perl-compatible regular expressions instead of standard or extended
# POSIX regular expressions. Only libpcre version 2 is supported.
#
# Define LIBPCREDIR=/foo/bar if your PCRE header and library files are in
# /foo/bar/include and /foo/bar/lib directories.
#

AC_ARG_WITH(libpcre1,
AS_HELP_STRING([--with-libpcre1],[DEPRECATED]),
    AC_MSG_ERROR([support for --with-libpcre1 has been removed. Use --with-libpcre2!])
    )

AC_ARG_WITH(libpcre,
AS_HELP_STRING([--with-libpcre],[synonym for --with-libpcre2]),
    if test "$withval" = "no"; then
	USE_LIBPCRE2=
    elif test "$withval" = "yes"; then
	USE_LIBPCRE2=YesPlease
    else
	USE_LIBPCRE2=YesPlease
	LIBPCREDIR=$withval
	AC_MSG_NOTICE([Setting LIBPCREDIR to $LIBPCREDIR])
        dnl USE_LIBPCRE2 can still be modified below, so don't substitute
        dnl it yet.
	GIT_CONF_SUBST([LIBPCREDIR])
    fi)

AC_ARG_WITH(libpcre2,
AS_HELP_STRING([--with-libpcre2],[support Perl-compatible regexes via libpcre2 (default is NO)])
AS_HELP_STRING([],           [ARG can be also prefix for libpcre library and headers]),
    if test -n "$USE_LIBPCRE2"; then
        AC_MSG_ERROR([Only supply one of --with-libpcre or its synonym --with-libpcre2!])
    fi

    if test "$withval" = "no"; then
	USE_LIBPCRE2=
    elif test "$withval" = "yes"; then
	USE_LIBPCRE2=YesPlease
    else
	USE_LIBPCRE2=YesPlease
	LIBPCREDIR=$withval
	AC_MSG_NOTICE([Setting LIBPCREDIR to $LIBPCREDIR])
        dnl USE_LIBPCRE2 can still be modified below, so don't substitute
        dnl it yet.
	GIT_CONF_SUBST([LIBPCREDIR])
    fi)
#
# Define HAVE_ALLOCA_H if you have working alloca(3) defined in that header.
AC_FUNC_ALLOCA
case $ac_cv_working_alloca_h in
    yes)    HAVE_ALLOCA_H=YesPlease;;
    *)      HAVE_ALLOCA_H='';;
esac
GIT_CONF_SUBST([HAVE_ALLOCA_H])
#
# Define NO_CURL if you do not have curl installed.  git-http-pull and
# git-http-push are not built, and you cannot use http:// and https://
# transports.
#
# Define CURLDIR=/foo/bar if your curl header and library files are in
# /foo/bar/include and /foo/bar/lib directories.
AC_ARG_WITH(curl,
AS_HELP_STRING([--with-curl],[support http(s):// transports (default is YES)])
AS_HELP_STRING([],           [ARG can be also prefix for curl library and headers]),
GIT_PARSE_WITH(curl))
#
# Define NO_EXPAT if you do not have expat installed.  git-http-push is
# not built, and you cannot push using http:// and https:// transports.
#
# Define EXPATDIR=/foo/bar if your expat header and library files are in
# /foo/bar/include and /foo/bar/lib directories.
AC_ARG_WITH(expat,
AS_HELP_STRING([--with-expat],
[support git-push using http:// and https:// transports via WebDAV (default is YES)])
AS_HELP_STRING([],            [ARG can be also prefix for expat library and headers]),
GIT_PARSE_WITH(expat))
#
# Define NO_FINK if you are building on Darwin/Mac OS X, have Fink
# installed in /sw, but don't want GIT to link against any libraries
# installed there.  If defined you may specify your own (or Fink's)
# include directories and library directories by defining CFLAGS
# and LDFLAGS appropriately.
#
# Define NO_DARWIN_PORTS if you are building on Darwin/Mac OS X,
# have DarwinPorts installed in /opt/local, but don't want GIT to
# link against any libraries installed there.  If defined you may
# specify your own (or DarwinPort's) include directories and
# library directories by defining CFLAGS and LDFLAGS appropriately.
#
# Define NO_MMAP if you want to avoid mmap.
#
# Define NO_ICONV if your libc does not properly support iconv.
AC_ARG_WITH(iconv,
AS_HELP_STRING([--without-iconv],
[if your architecture doesn't properly support iconv])
AS_HELP_STRING([--with-iconv=PATH],
[PATH is prefix for libiconv library and headers])
AS_HELP_STRING([],
[used only if you need linking with libiconv]),
GIT_PARSE_WITH(iconv))

## --enable-FEATURE[=ARG] and --disable-FEATURE
#
# Define USE_NSEC below if you want git to care about sub-second file mtimes
# and ctimes. Note that you need recent glibc (at least 2.2.4) for this, and
# it will BREAK YOUR LOCAL DIFFS! show-diff and anything using it will likely
# randomly break unless your underlying filesystem supports those sub-second
# times (my ext3 doesn't).
#
# Define USE_STDEV below if you want git to care about the underlying device
# change being considered an inode change from the update-index perspective.

#
# Allow user to set ETC_GITCONFIG variable
GIT_PARSE_WITH_SET_MAKE_VAR(gitconfig, ETC_GITCONFIG,
			Use VALUE instead of /etc/gitconfig as the
			global git configuration file.
			If VALUE is not fully qualified it will be interpreted
			as a path relative to the computed prefix at runtime.)

#
# Allow user to set ETC_GITATTRIBUTES variable
GIT_PARSE_WITH_SET_MAKE_VAR(gitattributes, ETC_GITATTRIBUTES,
			Use VALUE instead of /etc/gitattributes as the
			global git attributes file.
			If VALUE is not fully qualified it will be interpreted
			as a path relative to the computed prefix at runtime.)

#
# Allow user to set the default pager
GIT_PARSE_WITH_SET_MAKE_VAR(pager, DEFAULT_PAGER,
			Use VALUE as the fall-back pager instead of 'less'.
			This is used by things like 'git log' when the user
			does not specify a pager to use through alternate
			methods. eg: /usr/bin/pager)
#
# Allow user to set the default editor
GIT_PARSE_WITH_SET_MAKE_VAR(editor, DEFAULT_EDITOR,
			Use VALUE as the fall-back editor instead of 'vi'.
			This is used by things like 'git commit' when the user
			does not specify a preferred editor through other
			methods. eg: /usr/bin/editor)

#
# Define SHELL_PATH to provide path to shell.
GIT_ARG_SET_PATH(shell)
#
# Define PERL_PATH to provide path to Perl.
GIT_ARG_SET_PATH(perl)
#
# Define PYTHON_PATH to provide path to Python.
GIT_ARG_SET_PATH(python, allow-without)
#
# Define ZLIB_PATH to provide path to zlib.
GIT_ARG_SET_PATH(zlib)
#
# Declare the with-tcltk/without-tcltk options.
AC_ARG_WITH(tcltk,
AS_HELP_STRING([--with-tcltk],[use Tcl/Tk GUI (default is YES)])
AS_HELP_STRING([],[ARG is the full path to the Tcl/Tk interpreter.])
AS_HELP_STRING([],[Bare --with-tcltk will make the GUI part only if])
AS_HELP_STRING([],[Tcl/Tk interpreter will be found in a system.]),
GIT_PARSE_WITH(tcltk))
#


## Checks for programs.
AC_MSG_NOTICE([CHECKS for programs])
#
AC_PROG_CC([cc gcc])
AC_C_INLINE
case $ac_cv_c_inline in
  inline | yes | no) INLINE='';;
  *)                 INLINE=$ac_cv_c_inline ;;
esac
GIT_CONF_SUBST([INLINE])

# which switch to pass runtime path to dynamic libraries to the linker
AC_CACHE_CHECK([if linker supports -R], git_cv_ld_dashr, [
   SAVE_LDFLAGS="${LDFLAGS}"
   LDFLAGS="${SAVE_LDFLAGS} -R /"
   AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])], [git_cv_ld_dashr=yes], [git_cv_ld_dashr=no])
   LDFLAGS="${SAVE_LDFLAGS}"
])
if test "$git_cv_ld_dashr" = "yes"; then
   CC_LD_DYNPATH=-R
else
   AC_CACHE_CHECK([if linker supports -Wl,-rpath,], git_cv_ld_wl_rpath, [
      SAVE_LDFLAGS="${LDFLAGS}"
      LDFLAGS="${SAVE_LDFLAGS} -Wl,-rpath,/"
      AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])], [git_cv_ld_wl_rpath=yes], [git_cv_ld_wl_rpath=no])
      LDFLAGS="${SAVE_LDFLAGS}"
   ])
   if test "$git_cv_ld_wl_rpath" = "yes"; then
      CC_LD_DYNPATH=-Wl,-rpath,
   else
      AC_CACHE_CHECK([if linker supports -rpath], git_cv_ld_rpath, [
         SAVE_LDFLAGS="${LDFLAGS}"
         LDFLAGS="${SAVE_LDFLAGS} -rpath /"
         AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])], [git_cv_ld_rpath=yes], [git_cv_ld_rpath=no])
         LDFLAGS="${SAVE_LDFLAGS}"
      ])
      if test "$git_cv_ld_rpath" = "yes"; then
         CC_LD_DYNPATH=-rpath
      else
         AC_CACHE_CHECK([if linker supports -Wl,+b,], git_cv_ld_wl_b, [
            SAVE_LDFLAGS="${LDFLAGS}"
            LDFLAGS="${SAVE_LDFLAGS} -Wl,+b,/"
            AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])], [git_cv_ld_wl_b=yes], [git_cv_ld_wl_b=no])
            LDFLAGS="${SAVE_LDFLAGS}"
         ])
         if test "$git_cv_ld_wl_b" = "yes"; then
            CC_LD_DYNPATH=-Wl,+b,
          else
             CC_LD_DYNPATH=
             AC_MSG_WARN([linker does not support runtime path to dynamic libraries])
          fi
      fi
   fi
fi
GIT_CONF_SUBST([CC_LD_DYNPATH])
#AC_PROG_INSTALL		# needs install-sh or install.sh in sources
AC_CHECK_TOOLS(AR, [gar ar], :)
AC_CHECK_PROGS(TAR, [gtar tar])
AC_CHECK_PROGS(DIFF, [gnudiff gdiff diff])
# TCLTK_PATH will be set to some value if we want Tcl/Tk
# or will be empty otherwise.
if test -n "$NO_TCLTK"; then
  TCLTK_PATH=
else
  if test "$with_tcltk" = ""; then
  # No Tcl/Tk switches given. Do not check for Tcl/Tk, use bare 'wish'.
    TCLTK_PATH=wish
  elif test "$with_tcltk" = "yes"; then
  # Tcl/Tk check requested.
    AC_CHECK_PROGS(TCLTK_PATH, [wish], )
  else
    AC_MSG_RESULT([Using Tcl/Tk interpreter $with_tcltk])
    TCLTK_PATH="$with_tcltk"
  fi
fi
GIT_CONF_SUBST([TCLTK_PATH])
AC_CHECK_PROGS(ASCIIDOC, [asciidoc])
if test -n "$ASCIIDOC"; then
	AC_MSG_CHECKING([for asciidoc version])
	asciidoc_version=`$ASCIIDOC --version 2>/dev/null`
	case "${asciidoc_version}" in
	asciidoc' '8*)
		AC_MSG_RESULT([${asciidoc_version}])
		;;
	*)
		AC_MSG_RESULT([${asciidoc_version} (unknown)])
		;;
	esac
fi

## Checks for libraries.
AC_MSG_NOTICE([CHECKS for libraries])
#
# Define NO_OPENSSL environment variable if you do not have OpenSSL.
# Define NEEDS_SSL_WITH_CRYPTO if you need -lcrypto with -lssl (Darwin).

GIT_STASH_FLAGS($OPENSSLDIR)

AC_CHECK_LIB([crypto], [SHA1_Init],
[NEEDS_SSL_WITH_CRYPTO=],
[AC_CHECK_LIB([ssl], [SHA1_Init],
 [NEEDS_SSL_WITH_CRYPTO=YesPlease NO_OPENSSL=],
 [NEEDS_SSL_WITH_CRYPTO=          NO_OPENSSL=YesPlease])])

GIT_UNSTASH_FLAGS($OPENSSLDIR)

GIT_CONF_SUBST([NEEDS_SSL_WITH_CRYPTO])
GIT_CONF_SUBST([NO_OPENSSL])

#
# Handle the USE_LIBPCRE options potentially set above.
#

if test -n "$USE_LIBPCRE2"; then

GIT_STASH_FLAGS($LIBPCREDIR)

AC_CHECK_LIB([pcre2-8], [pcre2_config_8],
[USE_LIBPCRE2=YesPlease],
[USE_LIBPCRE2=])

GIT_UNSTASH_FLAGS($LIBPCREDIR)

GIT_CONF_SUBST([USE_LIBPCRE2])

fi

#
# Define NO_CURL if you do not have libcurl installed.  git-http-pull and
# git-http-push are not built, and you cannot use http:// and https://
# transports.

GIT_STASH_FLAGS($CURLDIR)

AC_CHECK_LIB([curl], [curl_global_init],
[NO_CURL=],
[NO_CURL=YesPlease])

GIT_UNSTASH_FLAGS($CURLDIR)

GIT_CONF_SUBST([NO_CURL])

if test -z "$NO_CURL"; then

AC_CHECK_PROG([CURL_CONFIG], [curl-config],
[curl-config],
[no])

if test $CURL_CONFIG != no; then
    GIT_CONF_SUBST([CURL_CONFIG])

    if test -z "$CURL_CONFIG_OPTS"; then
        CURL_CONFIG_OPTS="--libs"
    fi

    CURL_LDFLAGS=$($CURL_CONFIG $CURL_CONFIG_OPTS)
    AC_MSG_NOTICE([Setting CURL_LDFLAGS to '$CURL_LDFLAGS'])
    GIT_CONF_SUBST([CURL_LDFLAGS], [$CURL_LDFLAGS])
fi

fi


#
# Define NO_EXPAT if you do not have expat installed.  git-http-push is
# not built, and you cannot push using http:// and https:// transports.

GIT_STASH_FLAGS($EXPATDIR)

AC_CHECK_LIB([expat], [XML_ParserCreate],
[NO_EXPAT=],
[NO_EXPAT=YesPlease])

GIT_UNSTASH_FLAGS($EXPATDIR)

GIT_CONF_SUBST([NO_EXPAT])

#
# Define NEEDS_LIBICONV if linking with libc is not enough (Darwin and
# some Solaris installations).
# Define NO_ICONV if neither libc nor libiconv support iconv.

if test -z "$NO_ICONV"; then

GIT_STASH_FLAGS($ICONVDIR)

AC_DEFUN([ICONVTEST_SRC],
[AC_LANG_PROGRAM([#include <iconv.h>],
 [iconv_open("", "");])])

if test -n "$ICONVDIR"; then
   lib_order="-liconv -lc"
else
   lib_order="-lc -liconv"
fi

NO_ICONV=YesPlease

for l in $lib_order; do
    if test "$l" = "-liconv"; then
       NEEDS_LIBICONV=YesPlease
    else
       NEEDS_LIBICONV=
    fi

    old_LIBS="$LIBS"
    LIBS="$LIBS $l"
    AC_MSG_CHECKING([for iconv in $l])
    AC_LINK_IFELSE([ICONVTEST_SRC],
	[AC_MSG_RESULT([yes])
	NO_ICONV=
	break],
	[AC_MSG_RESULT([no])])
    LIBS="$old_LIBS"
done

#in case of break
LIBS="$old_LIBS"

GIT_UNSTASH_FLAGS($ICONVDIR)

GIT_CONF_SUBST([NEEDS_LIBICONV])
GIT_CONF_SUBST([NO_ICONV])

if test -n "$NO_ICONV"; then
    NEEDS_LIBICONV=
fi

fi

#
# Define NO_DEFLATE_BOUND if deflateBound is missing from zlib.

GIT_STASH_FLAGS($ZLIB_PATH)

AC_DEFUN([ZLIBTEST_SRC], [
AC_LANG_PROGRAM([#include <zlib.h>],
 [deflateBound(0, 0);])])
AC_MSG_CHECKING([for deflateBound in -lz])
old_LIBS="$LIBS"
LIBS="$LIBS -lz"
AC_LINK_IFELSE([ZLIBTEST_SRC],
	[AC_MSG_RESULT([yes])],
	[AC_MSG_RESULT([no])
	NO_DEFLATE_BOUND=yes])
LIBS="$old_LIBS"

GIT_UNSTASH_FLAGS($ZLIB_PATH)

GIT_CONF_SUBST([NO_DEFLATE_BOUND])

#
# Define NEEDS_SOCKET if linking with libc is not enough (SunOS,
# Patrick Mauritz).
AC_CHECK_LIB([c], [socket],
[NEEDS_SOCKET=],
[NEEDS_SOCKET=YesPlease])
GIT_CONF_SUBST([NEEDS_SOCKET])
test -n "$NEEDS_SOCKET" && LIBS="$LIBS -lsocket"

#
# The next few tests will define NEEDS_RESOLV if linking with
# libresolv provides some of the functions we would normally get
# from libc.
NEEDS_RESOLV=
#
# Define NO_INET_NTOP if linking with -lresolv is not enough.
# Solaris 2.7 in particular hos inet_ntop in -lresolv.
NO_INET_NTOP=
AC_CHECK_FUNC([inet_ntop],
    [],
    [AC_CHECK_LIB([resolv], [inet_ntop],
	[NEEDS_RESOLV=YesPlease],
	[NO_INET_NTOP=YesPlease])
])
GIT_CONF_SUBST([NO_INET_NTOP])
#
# Define NO_INET_PTON if linking with -lresolv is not enough.
# Solaris 2.7 in particular hos inet_pton in -lresolv.
NO_INET_PTON=
AC_CHECK_FUNC([inet_pton],
    [],
    [AC_CHECK_LIB([resolv], [inet_pton],
	[NEEDS_RESOLV=YesPlease],
	[NO_INET_PTON=YesPlease])
])
GIT_CONF_SUBST([NO_INET_PTON])
#
# Define NO_HSTRERROR if linking with -lresolv is not enough.
# Solaris 2.6 in particular has no hstrerror, even in -lresolv.
NO_HSTRERROR=
AC_CHECK_FUNC([hstrerror],
    [],
    [AC_CHECK_LIB([resolv], [hstrerror],
	[NEEDS_RESOLV=YesPlease],
	[NO_HSTRERROR=YesPlease])
])
GIT_CONF_SUBST([NO_HSTRERROR])

dnl This must go after all the possible places for its initialization,
dnl in the AC_CHECK_FUNC invocations above.
GIT_CONF_SUBST([NEEDS_RESOLV])
#
# If any of the above tests determined that -lresolv is needed at
# build-time, also set it here for remaining configure-time checks.
test -n "$NEEDS_RESOLV" && LIBS="$LIBS -lresolv"

AC_CHECK_LIB([c], [basename],
[NEEDS_LIBGEN=],
[NEEDS_LIBGEN=YesPlease])
GIT_CONF_SUBST([NEEDS_LIBGEN])
test -n "$NEEDS_LIBGEN" && LIBS="$LIBS -lgen"

AC_DEFUN([LIBINTL_SRC], [
AC_LANG_PROGRAM([[
#include <libintl.h>
]],[[
char *msg = gettext("test");
]])])

AC_MSG_CHECKING([if libc contains libintl])
AC_LINK_IFELSE([LIBINTL_SRC],
	[AC_MSG_RESULT([yes])
	LIBC_CONTAINS_LIBINTL=YesPlease],
	[AC_MSG_RESULT([no])
	LIBC_CONTAINS_LIBINTL=])
GIT_CONF_SUBST([LIBC_CONTAINS_LIBINTL])

#
# Define NO_GETTEXT if you don't want Git output to be translated.
# A translated Git requires GNU libintl or another gettext implementation
AC_CHECK_HEADER([libintl.h],
[NO_GETTEXT=],
[NO_GETTEXT=YesPlease])
GIT_CONF_SUBST([NO_GETTEXT])

if test -z "$NO_GETTEXT"; then
    test -n "$LIBC_CONTAINS_LIBINTL" || LIBS="$LIBS -lintl"
fi

## Checks for header files.
AC_MSG_NOTICE([CHECKS for header files])
#
# Define NO_SYS_SELECT_H if you don't have sys/select.h.
AC_CHECK_HEADER([sys/select.h],
[NO_SYS_SELECT_H=],
[NO_SYS_SELECT_H=UnfortunatelyYes])
GIT_CONF_SUBST([NO_SYS_SELECT_H])
#
# Define NO_POLL_H if you don't have poll.h
AC_CHECK_HEADER([poll.h],
[NO_POLL_H=],
[NO_POLL_H=UnfortunatelyYes])
GIT_CONF_SUBST([NO_POLL_H])
#
# Define NO_SYS_POLL_H if you don't have sys/poll.h
AC_CHECK_HEADER([sys/poll.h],
[NO_SYS_POLL_H=],
[NO_SYS_POLL_H=UnfortunatelyYes])
GIT_CONF_SUBST([NO_SYS_POLL_H])
#
# Define NO_INTTYPES_H if you don't have inttypes.h
AC_CHECK_HEADER([inttypes.h],
[NO_INTTYPES_H=],
[NO_INTTYPES_H=UnfortunatelyYes])
GIT_CONF_SUBST([NO_INTTYPES_H])
#
# Define OLD_ICONV if your library has an old iconv(), where the second
# (input buffer pointer) parameter is declared with type (const char **).
AC_DEFUN([OLDICONVTEST_SRC], [
AC_LANG_PROGRAM([[
#include <iconv.h>

extern size_t iconv(iconv_t cd,
		    char **inbuf, size_t *inbytesleft,
		    char **outbuf, size_t *outbytesleft);
]], [])])

GIT_STASH_FLAGS($ICONVDIR)

AC_MSG_CHECKING([for old iconv()])
AC_COMPILE_IFELSE([OLDICONVTEST_SRC],
	[AC_MSG_RESULT([no])],
	[AC_MSG_RESULT([yes])
	AC_DEFINE(HAVE_OLD_ICONV, 1)
	OLD_ICONV=UnfortunatelyYes])

GIT_UNSTASH_FLAGS($ICONVDIR)

GIT_CONF_SUBST([OLD_ICONV])

#
# Define ICONV_OMITS_BOM if you are on a system which
# iconv omits bom for utf-{16,32}
if test -z "$NO_ICONV"; then
AC_CACHE_CHECK([whether iconv omits bom for utf-16 and utf-32],
 [ac_cv_iconv_omits_bom],
[
old_LIBS="$LIBS"
if test -n "$NEEDS_LIBICONV"; then
	LIBS="$LIBS -liconv"
fi

AC_RUN_IFELSE(
	[AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT
	#include <iconv.h>
	#ifdef HAVE_OLD_ICONV
	typedef const char *iconv_ibp;
	#else
	typedef char *iconv_ibp;
	#endif
	],
	[[
	int v;
	iconv_t conv;
	char in[] = "a"; iconv_ibp pin = in;
	char out[20] = ""; char *pout = out;
	size_t isz = sizeof in;
	size_t osz = sizeof out;

	conv = iconv_open("UTF-16", "UTF-8");
	iconv(conv, &pin, &isz, &pout, &osz);
	iconv_close(conv);
	v = (unsigned char)(out[0]) + (unsigned char)(out[1]);
	return v != 0xfe + 0xff;
	]])],
	[ac_cv_iconv_omits_bom=no],
	[ac_cv_iconv_omits_bom=yes])

LIBS="$old_LIBS"
])
if test "x$ac_cv_iconv_omits_bom" = xyes; then
	ICONV_OMITS_BOM=Yes
else
	ICONV_OMITS_BOM=
fi
GIT_CONF_SUBST([ICONV_OMITS_BOM])
fi

## Checks for typedefs, structures, and compiler characteristics.
AC_MSG_NOTICE([CHECKS for typedefs, structures, and compiler characteristics])
#
TYPE_SOCKLEN_T
case $ac_cv_type_socklen_t in
  yes)	SOCKLEN_T='';;
  *)  	SOCKLEN_T=$git_cv_socklen_t_equiv;;
esac
GIT_CONF_SUBST([SOCKLEN_T])

#
# Define NO_STRUCT_ITIMERVAL if you don't have struct itimerval.
AC_CHECK_TYPES([struct itimerval],
[NO_STRUCT_ITIMERVAL=],
[NO_STRUCT_ITIMERVAL=UnfortunatelyYes],
[#include <sys/time.h>])
GIT_CONF_SUBST([NO_STRUCT_ITIMERVAL])
#
# Define USE_ST_TIMESPEC=YesPlease when stat.st_mtimespec.tv_nsec exists.
# Define NO_NSEC=YesPlease when neither stat.st_mtim.tv_nsec nor
# stat.st_mtimespec.tv_nsec exists.
AC_CHECK_MEMBER([struct stat.st_mtimespec.tv_nsec])
AC_CHECK_MEMBER([struct stat.st_mtim.tv_nsec])
if test x$ac_cv_member_struct_stat_st_mtimespec_tv_nsec = xyes; then
	USE_ST_TIMESPEC=YesPlease
	GIT_CONF_SUBST([USE_ST_TIMESPEC])
elif test x$ac_cv_member_struct_stat_st_mtim_tv_nsec != xyes; then
	NO_NSEC=YesPlease
	GIT_CONF_SUBST([NO_NSEC])
fi
#
# Define NO_D_TYPE_IN_DIRENT if your platform defines DT_UNKNOWN but lacks
# d_type in struct dirent (latest Cygwin -- will be fixed soonish).
AC_CHECK_MEMBER(struct dirent.d_type,
[NO_D_TYPE_IN_DIRENT=],
[NO_D_TYPE_IN_DIRENT=YesPlease],
[#include <dirent.h>])
GIT_CONF_SUBST([NO_D_TYPE_IN_DIRENT])
#
# Define NO_GECOS_IN_PWENT if you don't have pw_gecos in struct passwd
# in the C library.
AC_CHECK_MEMBER(struct passwd.pw_gecos,
[NO_GECOS_IN_PWENT=],
[NO_GECOS_IN_PWENT=YesPlease],
[#include <pwd.h>])
GIT_CONF_SUBST([NO_GECOS_IN_PWENT])
#
# Define NO_SOCKADDR_STORAGE if your platform does not have struct
# sockaddr_storage.
AC_CHECK_TYPE(struct sockaddr_storage,
[NO_SOCKADDR_STORAGE=],
[NO_SOCKADDR_STORAGE=YesPlease],[
#include <sys/types.h>
#include <sys/socket.h>
])
GIT_CONF_SUBST([NO_SOCKADDR_STORAGE])
#
# Define NO_IPV6 if you lack IPv6 support and getaddrinfo().
AC_CHECK_TYPE([struct addrinfo],[
 GIT_CHECK_FUNC([getaddrinfo],
  [NO_IPV6=],
  [NO_IPV6=YesPlease])
],[NO_IPV6=YesPlease],[
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
])
GIT_CONF_SUBST([NO_IPV6])
#
# Define NO_REGEX if your C library lacks regex support with REG_STARTEND
# feature.
AC_CACHE_CHECK([whether the platform regex supports REG_STARTEND],
 [ac_cv_c_regex_with_reg_startend], [
AC_EGREP_CPP(yippeeyeswehaveit,
	AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT
#include <regex.h>
],
[#ifdef REG_STARTEND
yippeeyeswehaveit
#endif
]),
	[ac_cv_c_regex_with_reg_startend=yes],
	[ac_cv_c_regex_with_reg_startend=no])
])
if test $ac_cv_c_regex_with_reg_startend = yes; then
	NO_REGEX=
else
	NO_REGEX=YesPlease
fi
GIT_CONF_SUBST([NO_REGEX])
#
# Define FREAD_READS_DIRECTORIES if your are on a system which succeeds
# when attempting to read from an fopen'ed directory.
AC_CACHE_CHECK([whether system succeeds to read fopen'ed directory],
 [ac_cv_fread_reads_directories],
[
AC_RUN_IFELSE(
	[AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT],
		[[
		FILE *f = fopen(".", "r");
		return f != NULL;]])],
	[ac_cv_fread_reads_directories=no],
	[ac_cv_fread_reads_directories=yes])
])
if test $ac_cv_fread_reads_directories = yes; then
	FREAD_READS_DIRECTORIES=UnfortunatelyYes
else
	FREAD_READS_DIRECTORIES=
fi
GIT_CONF_SUBST([FREAD_READS_DIRECTORIES])
#
# Define SNPRINTF_RETURNS_BOGUS if your are on a system which snprintf()
# or vsnprintf() return -1 instead of number of characters which would
# have been written to the final string if enough space had been available.
AC_CACHE_CHECK([whether snprintf() and/or vsnprintf() return bogus value],
 [ac_cv_snprintf_returns_bogus],
[
AC_RUN_IFELSE(
	[AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT
		#include "stdarg.h"

		int test_vsnprintf(char *str, size_t maxsize, const char *format, ...)
		{
		  int ret;
		  va_list ap;
		  va_start(ap, format);
		  ret = vsnprintf(str, maxsize, format, ap);
		  va_end(ap);
		  return ret;
		}],
		[[char buf[6];
		  if (test_vsnprintf(buf, 3, "%s", "12345") != 5
		      || strcmp(buf, "12")) return 1;
		  if (snprintf(buf, 3, "%s", "12345") != 5
		      || strcmp(buf, "12")) return 1]])],
	[ac_cv_snprintf_returns_bogus=no],
	[ac_cv_snprintf_returns_bogus=yes])
])
if test $ac_cv_snprintf_returns_bogus = yes; then
	SNPRINTF_RETURNS_BOGUS=UnfortunatelyYes
else
	SNPRINTF_RETURNS_BOGUS=
fi
GIT_CONF_SUBST([SNPRINTF_RETURNS_BOGUS])
#
# Define NEEDS_MODE_TRANSLATION if your OS strays from the typical file type
# bits in mode values.
AC_CACHE_CHECK([whether the platform uses typical file type bits],
 [ac_cv_sane_mode_bits], [
AC_EGREP_CPP(yippeeyeswehaveit,
	AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT],
[#if S_IFMT == 0170000 && \
	S_IFREG == 0100000 && S_IFDIR == 0040000 && S_IFLNK == 0120000 && \
	S_IFBLK == 0060000 && S_IFCHR == 0020000 && \
	S_IFIFO == 0010000 && S_IFSOCK == 0140000
yippeeyeswehaveit
#endif
]),
	[ac_cv_sane_mode_bits=yes],
	[ac_cv_sane_mode_bits=no])
])
if test $ac_cv_sane_mode_bits = yes; then
	NEEDS_MODE_TRANSLATION=
else
	NEEDS_MODE_TRANSLATION=UnfortunatelyYes
fi
GIT_CONF_SUBST([NEEDS_MODE_TRANSLATION])


## Checks for library functions.
## (in default C library and libraries checked by AC_CHECK_LIB)
AC_MSG_NOTICE([CHECKS for library functions])
#
# Define NO_LIBGEN_H if you don't have libgen.h.
AC_CHECK_HEADER([libgen.h],
[NO_LIBGEN_H=],
[NO_LIBGEN_H=YesPlease])
GIT_CONF_SUBST([NO_LIBGEN_H])
#
# Define HAVE_PATHS_H if you have paths.h.
AC_CHECK_HEADER([paths.h],
[HAVE_PATHS_H=YesPlease],
[HAVE_PATHS_H=])
GIT_CONF_SUBST([HAVE_PATHS_H])
#
# Define HAVE_LIBCHARSET_H if have libcharset.h
AC_CHECK_HEADER([libcharset.h],
[HAVE_LIBCHARSET_H=YesPlease],
[HAVE_LIBCHARSET_H=])
GIT_CONF_SUBST([HAVE_LIBCHARSET_H])
#
# Define HAVE_STRINGS_H if you have strings.h
AC_CHECK_HEADER([strings.h],
[HAVE_STRINGS_H=YesPlease],
[HAVE_STRINGS_H=])
GIT_CONF_SUBST([HAVE_STRINGS_H])
# Define CHARSET_LIB if libiconv does not export the locale_charset symbol
# and libcharset does
CHARSET_LIB=
AC_CHECK_LIB([iconv], [locale_charset],
       [CHARSET_LIB=-liconv],
       [AC_CHECK_LIB([charset], [locale_charset],
                     [CHARSET_LIB=-lcharset])])
GIT_CONF_SUBST([CHARSET_LIB])
#
# Define HAVE_CLOCK_GETTIME=YesPlease if clock_gettime is available.
GIT_CHECK_FUNC(clock_gettime,
	[HAVE_CLOCK_GETTIME=YesPlease],
	[HAVE_CLOCK_GETTIME=])
GIT_CONF_SUBST([HAVE_CLOCK_GETTIME])

AC_DEFUN([CLOCK_MONOTONIC_SRC], [
AC_LANG_PROGRAM([[
#include <time.h>
clockid_t id = CLOCK_MONOTONIC;
]])])

#
# Define HAVE_CLOCK_MONOTONIC=YesPlease if CLOCK_MONOTONIC is available.
AC_MSG_CHECKING([for CLOCK_MONOTONIC])
AC_COMPILE_IFELSE([CLOCK_MONOTONIC_SRC],
	[AC_MSG_RESULT([yes])
	HAVE_CLOCK_MONOTONIC=YesPlease],
	[AC_MSG_RESULT([no])
	HAVE_CLOCK_MONOTONIC=])
GIT_CONF_SUBST([HAVE_CLOCK_MONOTONIC])

#
# Define HAVE_SYNC_FILE_RANGE=YesPlease if sync_file_range is available.
GIT_CHECK_FUNC(sync_file_range,
	[HAVE_SYNC_FILE_RANGE=YesPlease],
	[HAVE_SYNC_FILE_RANGE=])
GIT_CONF_SUBST([HAVE_SYNC_FILE_RANGE])

#
# Define NO_SETITIMER if you don't have setitimer.
GIT_CHECK_FUNC(setitimer,
[NO_SETITIMER=],
[NO_SETITIMER=YesPlease])
GIT_CONF_SUBST([NO_SETITIMER])
#
# Define NO_STRCASESTR if you don't have strcasestr.
GIT_CHECK_FUNC(strcasestr,
[NO_STRCASESTR=],
[NO_STRCASESTR=YesPlease])
GIT_CONF_SUBST([NO_STRCASESTR])
#
# Define NO_MEMMEM if you don't have memmem.
GIT_CHECK_FUNC(memmem,
[NO_MEMMEM=],
[NO_MEMMEM=YesPlease])
GIT_CONF_SUBST([NO_MEMMEM])
#
# Define NO_STRLCPY if you don't have strlcpy.
GIT_CHECK_FUNC(strlcpy,
[NO_STRLCPY=],
[NO_STRLCPY=YesPlease])
GIT_CONF_SUBST([NO_STRLCPY])
#
# Define NO_UINTMAX_T if your platform does not have uintmax_t
AC_CHECK_TYPE(uintmax_t,
[NO_UINTMAX_T=],
[NO_UINTMAX_T=YesPlease],[
#include <inttypes.h>
])
GIT_CONF_SUBST([NO_UINTMAX_T])
#
# Define NO_STRTOUMAX if you don't have strtoumax in the C library.
GIT_CHECK_FUNC(strtoumax,
[NO_STRTOUMAX=],
[NO_STRTOUMAX=YesPlease])
GIT_CONF_SUBST([NO_STRTOUMAX])
#
# Define NO_SETENV if you don't have setenv in the C library.
GIT_CHECK_FUNC(setenv,
[NO_SETENV=],
[NO_SETENV=YesPlease])
GIT_CONF_SUBST([NO_SETENV])
#
# Define NO_UNSETENV if you don't have unsetenv in the C library.
GIT_CHECK_FUNC(unsetenv,
[NO_UNSETENV=],
[NO_UNSETENV=YesPlease])
GIT_CONF_SUBST([NO_UNSETENV])
#
# Define NO_MKDTEMP if you don't have mkdtemp in the C library.
GIT_CHECK_FUNC(mkdtemp,
[NO_MKDTEMP=],
[NO_MKDTEMP=YesPlease])
GIT_CONF_SUBST([NO_MKDTEMP])
#
# Define NO_INITGROUPS if you don't have initgroups in the C library.
GIT_CHECK_FUNC(initgroups,
[NO_INITGROUPS=],
[NO_INITGROUPS=YesPlease])
GIT_CONF_SUBST([NO_INITGROUPS])
#
# Define HAVE_GETDELIM if you have getdelim in the C library.
GIT_CHECK_FUNC(getdelim,
[HAVE_GETDELIM=YesPlease],
[HAVE_GETDELIM=])
GIT_CONF_SUBST([HAVE_GETDELIM])
#
#
# Define NO_MMAP if you want to avoid mmap.
#
# Define NO_ICONV if your libc does not properly support iconv.

AC_DEFUN([BSD_SYSCTL_SRC], [
AC_LANG_PROGRAM([[
#include <stddef.h>
#include <sys/types.h>
#include <sys/sysctl.h>
]],[[
int val, mib[2];
size_t len;
mib[0] = CTL_HW;
mib[1] = 1;
len = sizeof(val);
return sysctl(mib, 2, &val, &len, NULL, 0) ? 1 : 0;
]])])

#
# Define HAVE_BSD_SYSCTL=YesPlease if a BSD-compatible sysctl function is available.
AC_MSG_CHECKING([for BSD sysctl])
AC_COMPILE_IFELSE([BSD_SYSCTL_SRC],
	[AC_MSG_RESULT([yes])
	HAVE_BSD_SYSCTL=YesPlease],
	[AC_MSG_RESULT([no])
	HAVE_BSD_SYSCTL=])
GIT_CONF_SUBST([HAVE_BSD_SYSCTL])

## Other checks.
# Define NO_SYMLINK_HEAD if you never want .git/HEAD to be a symbolic link.
# Enable it on Windows.  By default, symrefs are still used.
#
# Define NO_PTHREADS if we do not have pthreads.
#
# Define PTHREAD_LIBS to the linker flag used for Pthread support.
AC_DEFUN([PTHREADTEST_SRC], [
AC_LANG_PROGRAM([[
#include <pthread.h>
static void *noop(void *ignore) { return ignore; }
]], [[
	pthread_mutex_t test_mutex;
	pthread_key_t test_key;
	pthread_t th;
	int retcode = 0;
	void *ret = (void *)0;
	retcode |= pthread_key_create(&test_key, (void *)0);
	retcode |= pthread_mutex_init(&test_mutex,(void *)0);
	retcode |= pthread_mutex_lock(&test_mutex);
	retcode |= pthread_mutex_unlock(&test_mutex);
	retcode |= pthread_create(&th, ret, noop, ret);
	retcode |= pthread_join(th, &ret);
	return retcode;
]])])

dnl AC_LANG_CONFTEST([AC_LANG_PROGRAM(
dnl   [[#include <pthread.h>]],
dnl   [[pthread_mutex_t test_mutex;]]
dnl )])

NO_PTHREADS=UnfortunatelyYes
PTHREAD_LIBS=

if test -n "$USER_NOPTHREAD"; then
   AC_MSG_NOTICE([Skipping POSIX Threads at user request.])
# handle these separately since PTHREAD_CFLAGS could be '-lpthreads
# -D_REENTRANT' or some such.
elif test -z "$PTHREAD_CFLAGS"; then
  threads_found=no
  # Attempt to compile and link some code using pthreads to determine
  # required linker flags. The order is somewhat important here: We
  # first try it without any extra flags, to catch systems where
  # pthreads are part of the C library, then go on testing various other
  # flags. We do so to avoid false positives. For example, on Mac OS X
  # pthreads are part of the C library; moreover, the compiler allows us
  # to add "-mt" to the CFLAGS (although it will do nothing except
  # trigger a warning about an unused flag). Hence if we checked for
  # "-mt" before "" we would end up picking it. But unfortunately this
  # would then trigger compiler warnings on every single file we compile.
  for opt in "" -mt -pthread -lpthread; do
     old_CFLAGS="$CFLAGS"
     old_LIBS="$LIBS"
     case "$opt" in
        -l*)  LIBS="$opt $LIBS" ;;
        *)    CFLAGS="$opt $CFLAGS" ;;
     esac

     AC_MSG_CHECKING([for POSIX Threads with '$opt'])
     AC_LINK_IFELSE([PTHREADTEST_SRC],
	[AC_MSG_RESULT([yes])
		NO_PTHREADS=
		PTHREAD_LIBS="$opt"
		PTHREAD_CFLAGS="$opt"
		threads_found=yes
		break
	],
	[AC_MSG_RESULT([no])])
      CFLAGS="$old_CFLAGS"
      LIBS="$old_LIBS"
  done
  if test $threads_found != yes; then
    AC_CHECK_LIB([pthread], [pthread_create],
	[PTHREAD_LIBS="-lpthread"],
	[NO_PTHREADS=UnfortunatelyYes])
  fi
else
  old_CFLAGS="$CFLAGS"
  CFLAGS="$PTHREAD_CFLAGS $CFLAGS"
  AC_MSG_CHECKING([for POSIX Threads with '$PTHREAD_CFLAGS'])
  AC_LINK_IFELSE([PTHREADTEST_SRC],
	[AC_MSG_RESULT([yes])
		NO_PTHREADS=
		PTHREAD_LIBS="$PTHREAD_CFLAGS"
	],
	[AC_MSG_RESULT([no])])

  CFLAGS="$old_CFLAGS"
fi

CFLAGS="$old_CFLAGS"

GIT_CONF_SUBST([PTHREAD_CFLAGS])
GIT_CONF_SUBST([PTHREAD_LIBS])
GIT_CONF_SUBST([NO_PTHREADS])

## Output files
AC_CONFIG_FILES(["${config_file}":"${config_in}"])
AC_OUTPUT
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