diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3fb062c7e4..5a93a8c4c7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -211,7 +211,7 @@ ADD_CUSTOM_TARGET(uninstall
 # Compiler dependent definitions
 
 
-if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "(Apple)?Clang")
   # using Clang
     MESSAGE("-- Current build compiler is Clang")
     ADD_DEFINITIONS(-D_ISOC9X_SOURCE)