CMAKE_CXX_COMPILER_ID is AppleClang for MacOS for recent versions of CMake.

cmake/modules/CheckCompiler.cmake

@@ -163,7 +163,7 @@ set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${CMAKE_THREAD_FLAG}")
 
 if(cxx11)
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
-  if(${CMAKE_CXX_COMPILER_ID} STREQUAL Clang)
+  if(${CMAKE_CXX_COMPILER_ID} MATCHES Clang)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wc++11-narrowing -Wsign-compare -Wsometimes-uninitialized -Wconditional-uninitialized -Wheader-guard -Warray-bounds -Wcomment -Wtautological-compare -Wstrncat-size -Wloop-analysis -Wbool-conversion")
   endif()
 endif()

cmake/modules/SearchInstalledSoftware.cmake

@@ -201,7 +201,7 @@ if(builtin_lzma)
     set(LZMA_LIBRARIES ${CMAKE_BINARY_DIR}/LZMA/src/LZMA/lib/liblzma.lib)
     set(LZMA_INCLUDE_DIR ${CMAKE_BINARY_DIR}/LZMA/src/LZMA/include)
   else()
-    if(CMAKE_CXX_COMPILER_ID STREQUAL Clang)
+    if(CMAKE_CXX_COMPILER_ID MATCHES Clang)
       set(LZMA_CFLAGS "-Wno-format-nonliteral")
       set(LZMA_LDFLAGS "-Qunused-arguments")
     elseif( CMAKE_CXX_COMPILER_ID STREQUAL Intel)

cmake/modules/SetUpMacOS.cmake

@@ -20,7 +20,7 @@ if (CMAKE_SYSTEM_NAME MATCHES Darwin)
                   COMMAND cut -d . -f 2
                   OUTPUT_VARIABLE MACOSX_MINOR OUTPUT_STRIP_TRAILING_WHITESPACE)
 
-  if(MACOSX_VERSION VERSION_GREATER 10.7 AND ${CMAKE_CXX_COMPILER_ID} STREQUAL Clang)
+  if(MACOSX_VERSION VERSION_GREATER 10.7 AND ${CMAKE_CXX_COMPILER_ID} MATCHES Clang)
     set(libcxx ON CACHE BOOL "Build using libc++" FORCE)
   endif()
 

core/meta/CMakeLists.txt

@@ -19,14 +19,10 @@ else()
   set_source_files_properties(${CMAKE_CURRENT_SOURCE_DIR}/src/TClingCallbacks.cxx COMPILE_FLAGS -fno-rtti)
 endif()
 
-if(${CMAKE_CXX_COMPILER_ID} STREQUAL Clang)
-   # This to avoid warning coming from  message coming from llvm/src/tools/clang/include/clang/Sema/Lookup.h:441
-   # in clang + llvm version r227800.
-   set(CLANG_ADDITIONAL_FLAGS "-Wno-conditional-uninitialized")
-   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CLANG_ADDITIONAL_FLAGS}")
-endif()
-
-ROOT_ADD_CXX_FLAG(CMAKE_CXX_FLAGS  -Wno-shadow)
+# This to avoid warning coming from  message coming from llvm/src/tools/clang/include/clang/Sema/Lookup.h:441
+# in clang + llvm version r227800.
+ROOT_ADD_CXX_FLAG(CMAKE_CXX_FLAGS -Wno-conditional-uninitialized)
+ROOT_ADD_CXX_FLAG(CMAKE_CXX_FLAGS -Wno-shadow)
 
 ROOT_OBJECT_LIBRARY(MetaLLVM ${sources})
 add_dependencies(MetaLLVM CLING)

graf2d/qt/CMakeLists.txt

@@ -9,11 +9,9 @@ set(headers TGQt.h TQtTimer.h TQtApplication.h TQtBrush.h
             TQMimeTypes.h TQtClientFilter.h TQtClientWidget.h TQtWidget.h
             TQtMarker.h TQtTimer.h TQtRootSlot.h TQtPadFont.h)
 
-if(CMAKE_COMPILER_IS_GNUCXX)
-  add_definitions(-Wno-deprecated-register -Wno-uninitialized)
-elseif(CMAKE_CXX_COMPILER_ID STREQUAL Clang)
-  add_definitions(-Wno-deprecated -Wno-uninitialized)
-endif()
+ROOT_ADD_CXX_FLAG(CMAKE_CXX_FLAGS -Wno-deprecated-register)
+ROOT_ADD_CXX_FLAG(CMAKE_CXX_FLAGS -Wno-deprecated)
+ROOT_ADD_CXX_FLAG(CMAKE_CXX_FLAGS -Wno-uninitialized)
 
 QT4_WRAP_CPP(mocfiles inc/TQtWidget.h inc/TQtEmitter.h inc/TQtClientFilter.h
                       inc/TQtClientGuard.h inc/TQtClientWidget.h inc/TQtTimer.h

gui/qtroot/CMakeLists.txt

@@ -5,11 +5,9 @@
 
 include(${QT_USE_FILE})
 
-if(CMAKE_COMPILER_IS_GNUCXX)
-  add_definitions(-Wno-deprecated-register -Wno-uninitialized)
-elseif(CMAKE_CXX_COMPILER_ID STREQUAL Clang)
-  add_definitions(-Wno-deprecated -Wno-uninitialized)
-endif()
+ROOT_ADD_CXX_FLAG(CMAKE_CXX_FLAGS -Wno-deprecated-register)
+ROOT_ADD_CXX_FLAG(CMAKE_CXX_FLAGS -Wno-deprecated)
+ROOT_ADD_CXX_FLAG(CMAKE_CXX_FLAGS -Wno-uninitialized)
 
 ROOT_GENERATE_DICTIONARY(G__QtRoot *.h MODULE QtRoot LINKDEF LinkDef.h)
 

misc/memstat/CMakeLists.txt

@@ -3,9 +3,7 @@
 # @author Pere Mato, CERN
 ############################################################################
 
-if(CMAKE_COMPILER_IS_GNUCXX OR ${CMAKE_CXX_COMPILER_ID} STREQUAL Clang)
-   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-deprecated-declarations")
-endif()
+ROOT_ADD_CXX_FLAG(CMAKE_CXX_FLAGS -Wno-deprecated-declarations)
 
 set(sources TMemStat.cxx TMemStatMng.cxx TMemStatBacktrace.cxx TMemStatHelpers.cxx TMemStatHook.cxx)
 set(headers TMemStatHelpers.h TMemStat.h TMemStatBacktrace.h TMemStatDef.h TMemStatMng.h TMemStatHook.h )