#                                               -*- Autoconf -*-
# mixture configure.ac
# (with some code borrowed from RcppArmadillo configure.ac
# and ARTP2 configure.ac)
#
# Process this file with autoconf to produce a configure script.

AC_PREREQ([2.69])

AC_INIT(mixture, m4_esyscmd_s([awk '/^Version:/ {print $2}' DESCRIPTION]))

## Set R_HOME, respecting an environment variable if one is set
: ${R_HOME=$(R RHOME)}
if test -z "${R_HOME}"; then
  AC_MSG_ERROR([Could not determine R_HOME.])
fi

## Use R to set CXX and CXXFLAGS
CXX=$(${R_HOME}/bin/R CMD config CXX)
CXXFLAGS=$("${R_HOME}/bin/R" CMD config CXXFLAGS)

## We are using C++
AC_LANG(C++)
AC_REQUIRE_CPP

dnl this the meat of R's m4/openmp.m4
  OPENMP_[]_AC_LANG_PREFIX[]FLAGS=
  AC_ARG_ENABLE([openmp],
    [AS_HELP_STRING([--disable-openmp], [do not use OpenMP])])
  if test "$enable_openmp" != no; then
    AC_CACHE_CHECK([for $[]_AC_CC[] option to support OpenMP],
      [ac_cv_prog_[]_AC_LANG_ABBREV[]_openmp],
      [AC_LINK_IFELSE([_AC_LANG_OPENMP],
	 [ac_cv_prog_[]_AC_LANG_ABBREV[]_openmp='none needed'],
	 [ac_cv_prog_[]_AC_LANG_ABBREV[]_openmp='unsupported'
	  for ac_option in -fopenmp -xopenmp -qopenmp \
                           -openmp -mp -omp -qsmp=omp -homp \
			   -fopenmp=libomp \
                           -Popenmp --openmp; do
	    ac_save_[]_AC_LANG_PREFIX[]FLAGS=$[]_AC_LANG_PREFIX[]FLAGS
	    _AC_LANG_PREFIX[]FLAGS="$[]_AC_LANG_PREFIX[]FLAGS $ac_option"
	    AC_LINK_IFELSE([_AC_LANG_OPENMP],
	      [ac_cv_prog_[]_AC_LANG_ABBREV[]_openmp=$ac_option])
	    _AC_LANG_PREFIX[]FLAGS=$ac_save_[]_AC_LANG_PREFIX[]FLAGS
	    if test "$ac_cv_prog_[]_AC_LANG_ABBREV[]_openmp" != unsupported; then
	      break
	    fi
	  done])])
    case $ac_cv_prog_[]_AC_LANG_ABBREV[]_openmp in #(
      "none needed" | unsupported)
	;; #(
      *)
	OPENMP_[]_AC_LANG_PREFIX[]FLAGS=$ac_cv_prog_[]_AC_LANG_ABBREV[]_openmp ;;
    esac
  fi


# Following lines kindly supplied by Dirk Eddelbuettel
## Use gsl-config to find arguments for compiler and linker flags
##
## Check for non-standard programs: gsl-config(1)
AC_PATH_PROG([GSL_CONFIG], [gsl-config])
## If gsl-config was found, let's use it
if test "${GSL_CONFIG}" != ""; then
   # Use gsl-config for header and linker arguments
   GSL_CFLAGS=`${GSL_CONFIG} --cflags`
   GSL_LIBS=`${GSL_CONFIG} --libs`
   CFLAGS="$CFLAGS $GSL_CFLAGS"  # kindly supplied by Ray Brownrigg
else
   AC_MSG_ERROR([gsl-config not found, is GSL installed?])
fi

# Now substitute these variables in src/Makevars.in to create src/Makevars
AC_SUBST(GSL_CFLAGS) 
AC_SUBST(GSL_LIBS)
AC_SUBST(OPENMP_CXXFLAGS)
AC_CONFIG_FILES([src/Makevars])
AC_OUTPUT