diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6daae58..af06637 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,7 +7,7 @@ PROJECT( fc )
 set( CMAKE_CXX_STANDARD 14 )
 SET( CMAKE_CXX_STANDARD_REQUIRED ON )
 
-if( "${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" )
+if( "${CMAKE_CXX_COMPILER_ID}" MATCHES "^(Apple)?Clang|GNU$" )
   set( CMAKE_CXX_EXTENSIONS ON ) # for __int128 support
 else( GNU )
   set( CMAKE_CXX_EXTENSIONS OFF )