CMake: Fix building with backward compatible render interfaces

CMake/DependenciesForBackends.cmake

@@ -65,7 +65,7 @@ if(RMLUI_BACKEND MATCHES "^SDL")
 endif()
 
 # GLFW
-if(RMLUI_BACKEND MATCHES "^GLFW")
+if(RMLUI_BACKEND MATCHES "^(BackwardCompatible_)?GLFW")
 	find_package("glfw3" "3.3")
 
 	# Instead of relying on the <package_name>_FOUND variable, we check directly for the target

Samples/basic/CMakeLists.txt

@@ -34,6 +34,6 @@ if(RMLUI_FONT_ENGINE_ENABLED)
 	if(RMLUI_BACKEND MATCHES "^Win32")
 		add_subdirectory("ime")
 	else()
-		message(STATUS "IME sample disabled due to RMLUI_BACKEND not being prefixed by Win32")
+		message(STATUS "IME sample disabled - only available with Win32 backends, see RMLUI_BACKEND")
 	endif()
 endif()