Don't use -Wcomma in old versions of clang

Author: baldurk

CMakeLists.txt

@@ -328,7 +328,11 @@ if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
     endif()
 
     if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-        list(APPEND warning_flags -Wnewline-eof -Wunreachable-code-break -Wclass-varargs -Wcomma -Wstring-conversion)
+        list(APPEND warning_flags -Wnewline-eof -Wunreachable-code-break -Wclass-varargs -Wstring-conversion)
+    endif()
+
+    if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 3.9)
+        list(APPEND warning_flags -Wcomma)
     endif()
 
     if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0 AND NOT APPLE)

qrenderdoc/CMakeLists.txt

@@ -168,7 +168,7 @@ if(CMAKE_COMPILER_IS_GNUCXX)
         "QMAKE_CXXFLAGS+=-Wno-unknown-warning -Wno-implicit-fallthrough -Wno-cast-function-type -Wno-stringop-truncation\n")
 endif()
 
-if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 3.9)
     file(APPEND
         ${CMAKE_BINARY_DIR}/qrenderdoc/qrenderdoc_cmake.pri
         "QMAKE_CXXFLAGS+=-Wno-comma\n")