smarter MY_CHECK_AND_SET_COMPILER_FLAG

If a flag is supported only for C or C++ - add it to the
corresponding compiler option list. Old behavior was to
add always to both, but only if supported in both.

cmake/check_compiler_flag.cmake

@@ -37,16 +37,16 @@ FUNCTION(MY_CHECK_AND_SET_COMPILER_FLAG flag)
   ENDIF()
   MY_CHECK_C_COMPILER_FLAG(${flag} HAVE_C_${flag})
   MY_CHECK_CXX_COMPILER_FLAG(${flag} HAVE_CXX_${flag})
-  IF (HAVE_C_${flag} AND HAVE_CXX_${flag})
-    IF(ARGN)
-      FOREACH(type ${ARGN})
-        SET(CMAKE_C_FLAGS_${type} "${CMAKE_C_FLAGS_${type}} ${flag}" PARENT_SCOPE)
-        SET(CMAKE_CXX_FLAGS_${type} "${CMAKE_CXX_FLAGS_${type}} ${flag}" PARENT_SCOPE)
-      ENDFOREACH()
-    ELSE()
-      SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${flag}" PARENT_SCOPE)
-      SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${flag}" PARENT_SCOPE)
+  FOREACH(lang C CXX)
+    IF (HAVE_${lang}_${flag})
+      IF(ARGN)
+        FOREACH(type ${ARGN})
+          SET(CMAKE_${lang}_FLAGS_${type} "${CMAKE_${lang}_FLAGS_${type}} ${flag}" PARENT_SCOPE)
+        ENDFOREACH()
+      ELSE()
+        SET(CMAKE_${lang}_FLAGS "${CMAKE_${lang}_FLAGS} ${flag}" PARENT_SCOPE)
+      ENDIF()
     ENDIF()
-  ENDIF()
+  ENDFOREACH()
 ENDFUNCTION()