Core/Build: Enable Clang PCH support and OS X specific features

Core: Fix warnings here and there

cmake/compiler/gcc/settings.cmake

@@ -1,24 +1,24 @@
 # Set build-directive (used in core to tell which buildtype we used)
 add_definitions(-D_BUILD_DIRECTIVE='"${CMAKE_BUILD_TYPE}"')
 
-add_definitions(-fno-delete-null-pointer-checks)
-
 if(PLATFORM EQUAL 32)
   # Required on 32-bit systems to enable SSE2 (standard on x64)
-  add_definitions(-msse2 -mfpmath=sse)
+  set(SSE_FLAGS "-msse2 -mfpmath=sse")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${SSE_FLAGS}")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${SSE_FLAGS}")
 endif()
 add_definitions(-DHAVE_SSE2 -D__SSE2__)
-message(STATUS "GCC: SSE2 flags forced")
+message(STATUS "GCC: SFMT enabled, SSE2 flags forced")
 
 if( WITH_WARNINGS )
-  add_definitions(-Wall -Wfatal-errors -Wextra)
+  set(WARNING_FLAGS "-W -Wall -Wextra -Wwrite-strings -Winit-self -Woverloaded-virtual -Winvalid-pch -Wfatal-errors")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${WARNING_FLAGS}")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${WARNING_FLAGS}")
   message(STATUS "GCC: All warnings enabled")
-else()
-  add_definitions(--no-warnings)
-  message(STATUS "GCC: All warnings disabled")
 endif()
 
 if( WITH_COREDEBUG )
-  add_definitions(-ggdb3)
-  message(STATUS "GCC: Debug-flags set (-ggdb3)")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g3")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g3")
+  message(STATUS "GCC: Debug-flags set (-g3)")
 endif()