CMake: fix detection of GCC 4.8

extras/CompileOptions.cmake

@@ -34,7 +34,7 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "(GNU|Clang)")
 endif()
 
 if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-	if((CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 4.8) AND(NOT ${COVERAGE}))
+	if((CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 4.9) AND(NOT ${COVERAGE}))
 		add_compile_options(-g -Og)
 	else() # GCC 4.8
 		add_compile_options(