Buildsystem/GCC: Enforce version 4.7.2 and enable c++11 compilation

cmake/compiler/gcc/settings.cmake

@@ -1,6 +1,15 @@
 # Set build-directive (used in core to tell which buildtype we used)
 add_definitions(-D_BUILD_DIRECTIVE='"${CMAKE_BUILD_TYPE}"')
 
+set(GCC_EXPECTED_VERSION 4.7.2)
+
+if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS GCC_EXPECTED_VERSION)
+  message(FATAL_ERROR "GCC: TrinityCore requires version ${GCC_EXPECTED_VERSION} to build but found ${CMAKE_CXX_COMPILER_VERSION}")
+endif()
+
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+message(STATUS "GCC: Enabled c++11 support")
+
 if(PLATFORM EQUAL 32)
   # Required on 32-bit systems to enable SSE2 (standard on x64)
   set(SSE_FLAGS "-msse2 -mfpmath=sse")