https://github.com/Kitware/CMake
Revision 1c14691a86ab8c6939dd04707dc2a92125fa8629 authored by Raul Tambre on 07 February 2021, 09:27:21 UTC, committed by Brad King on 09 July 2021, 15:27:47 UTC
Clang does not define `__STDC__` if in MSVC compatibility mode, but does
define `__STDC_VERSION__`.  Avoid the fallback for this combination.

This backports commit 7596d8b951 (CMakeCCompilerId: Fix C standard
detection in Clang MSVC mode, 2021-02-07, v3.21.0-rc1~587^2~14) to the
3.20 release series.  This is needed since commit 5115dd1e2c (IntelLLVM:
Fix C/C++ standard level flags on Windows, 2021-07-07, v3.21.0-rc3~7^2^2)
now that we activate C/C++ standard level logic for IntelLLVM when
targeting the MSVC ABI.
1 parent 5115dd1
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Tip revision: 1c14691a86ab8c6939dd04707dc2a92125fa8629 authored by Raul Tambre on 07 February 2021, 09:27:21 UTC
CMakeCCompilerId: Fix C standard detection in Clang and IntelLLVM MSVC mode
Tip revision: 1c14691
CheckOBJCCompilerFlag.cmake
# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.

#[=======================================================================[.rst:
CheckOBJCCompilerFlag
---------------------

.. versionadded:: 3.16

Check whether the Objective-C compiler supports a given flag.

.. command:: check_objc_compiler_flag

  .. code-block:: cmake

    check_objc_compiler_flag(<flag> <var>)

  Check that the ``<flag>`` is accepted by the compiler without
  a diagnostic.  Stores the result in an internal cache entry
  named ``<var>``.

This command temporarily sets the ``CMAKE_REQUIRED_DEFINITIONS`` variable
and calls the ``check_objc_source_compiles`` macro from the
:module:`CheckOBJCSourceCompiles` module.  See documentation of that
module for a listing of variables that can otherwise modify the build.

A positive result from this check indicates only that the compiler did not
issue a diagnostic message when given the flag.  Whether the flag has any
effect or even a specific one is beyond the scope of this module.

.. note::
  Since the :command:`try_compile` command forwards flags from variables
  like :variable:`CMAKE_OBJC_FLAGS <CMAKE_<LANG>_FLAGS>`, unknown flags
  in such variables may cause a false negative for this check.
#]=======================================================================]

include_guard(GLOBAL)
include(CheckOBJCSourceCompiles)
include(Internal/CheckCompilerFlag)

macro (CHECK_OBJC_COMPILER_FLAG _FLAG _RESULT)
  cmake_check_compiler_flag(OBJC "${_FLAG}" ${_RESULT})
endmacro ()
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