CMakeLists.txt: activate warning flags for Clang as well

Author: rouault

CMakeLists.txt

@@ -185,7 +185,7 @@ option(WITH_GENERIC_NINT "generic rounding" OFF)
 # PERLV_ld_DETECT?
 
 # Add compiler flags for warnings
-if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_COMPILER_IS_GNUCC)
+if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_COMPILER_IS_GNUCC OR CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Werror=format-security")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Werror=format-security")
 endif()