CompilerID: Compiler extensions default detection

1 files changed, 12 insertions, 0 deletions

diff --git a/Modules/CMakeCXXCompilerId.cpp.in b/Modules/CMakeCXXCompilerId.cpp.in
index 51c901eb09..cdf9c1828a 100644
--- a/Modules/CMakeCXXCompilerId.cpp.in
+++ b/Modules/CMakeCXXCompilerId.cpp.in
@@ -65,6 +65,17 @@ const char* info_language_standard_default = "INFO" ":" "standard_default["
 #endif
 "]";
 
+const char* info_language_extensions_default = "INFO" ":" "extensions_default["
+// !defined(_MSC_VER) to exclude Clang's MSVC compatibility mode.
+#if (defined(__clang__) || defined(__GNUC__) ||                               \
+     defined(__TI_COMPILER_VERSION__)) &&                                     \
+  !defined(__STRICT_ANSI__) && !defined(_MSC_VER)
+  "ON"
+#else
+  "OFF"
+#endif
+"]";
+
 /*--------------------------------------------------------------------------*/
 
 int main(int argc, char* argv[])
@@ -88,6 +99,7 @@ int main(int argc, char* argv[])
   require += info_cray[argc];
 #endif
   require += info_language_standard_default[argc];
+  require += info_language_extensions_default[argc];
   (void)argv;
   return require;
 }