Support coloured output for GCC

CMakeLists.txt

@@ -263,6 +263,9 @@ if (STORM_COMPILER_CLANG OR STORM_COMPILER_APPLECLANG)
         set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-export_dynamic")
     endif()
 elseif (STORM_COMPILER_GCC)
+    if(FORCE_COLOR)
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fdiagnostics-color=always")
+    endif()
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14")
     set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -fprefetch-loop-arrays")
     set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -rdynamic")