[cmake] Use -std=gnu++11 to fix alloca() on NetBSD

Prefer using '-std=gnu++11' over '-std=c++11' when available, as NetBSD exposes the correct alloca() implementation only with gnu* C/C++ standards. Differential Revision: https://reviews.llvm.org/D55477 llvm-svn: 348854
llvm · Dec 11, 2018 · e9d4267 · e9d4267
1 parent b51283b
commit e9d4267
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Showing 2 changed files with 6 additions and 2 deletions.
diff --git a/openmp/cmake/HandleOpenMPOptions.cmake b/openmp/cmake/HandleOpenMPOptions.cmake
@@ -13,4 +13,7 @@ if (${OPENMP_ENABLE_WERROR})
   append_if(OPENMP_HAVE_WERROR_FLAG "-Werror" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
 endif()
 
-append_if(OPENMP_HAVE_STD_CPP11_FLAG "-std=c++11" CMAKE_CXX_FLAGS)
+append_if(OPENMP_HAVE_STD_GNUPP11_FLAG "-std=gnu++11" CMAKE_CXX_FLAGS)
+if (NOT OPENMP_HAVE_STD_GNUPP11_FLAG)
+  append_if(OPENMP_HAVE_STD_CPP11_FLAG "-std=c++11" CMAKE_CXX_FLAGS)
+endif()
diff --git a/openmp/cmake/config-ix.cmake b/openmp/cmake/config-ix.cmake
@@ -3,4 +3,5 @@ include(CheckCXXCompilerFlag)
 
 check_c_compiler_flag(-Werror OPENMP_HAVE_WERROR_FLAG)
 
-check_cxx_compiler_flag(-std=c++11 OPENMP_HAVE_STD_CPP11_FLAG)
+check_cxx_compiler_flag(-std=gnu++11 OPENMP_HAVE_STD_GNUPP11_FLAG)
+check_cxx_compiler_flag(-std=c++11 OPENMP_HAVE_STD_CPP11_FLAG)