1 2set(_cmake_oldestSupported "(__GNUC__ * 100 + __GNUC_MINOR__) >= 304") 3 4# GNU 4.7 correctly sets __STDC_VERSION__ to 201112L, but GNU 4.6 sets it 5# to 201000L. As the former is strictly greater than the latter, test only 6# for the latter. If in the future CMake learns about a C feature which was 7# introduced with GNU 4.7, that should test for the correct version, similar 8# to the distinction between __cplusplus and __GXX_EXPERIMENTAL_CXX0X__ tests. 9set(GNU46_C11 "(__GNUC__ * 100 + __GNUC_MINOR__) >= 406 && defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201000L") 10set(_cmake_feature_test_c_static_assert "${GNU46_C11}") 11# Since 3.4 at least: 12set(GNU34_C99 "(__GNUC__ * 100 + __GNUC_MINOR__) >= 304 && defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L") 13set(_cmake_feature_test_c_restrict "${GNU34_C99}") 14set(_cmake_feature_test_c_variadic_macros "${GNU34_C99}") 15 16set(GNU_C90 "${_cmake_oldestSupported}") 17set(_cmake_feature_test_c_function_prototypes "${GNU_C90}") 18