+SDL_LDFLAGS := $(SDL_EXTRA_LIBS) $(shell sdl-config --libs)
+
+X11_CFLAGS = $(X11_INCL)
+X11_LDFLAGS = $(X11_LIBS) -lX11
+
+ifeq ($(USE_SDL),true)
+SYS_CFLAGS = $(SDL_CFLAGS)
+SYS_LDFLAGS = $(SDL_LDFLAGS)
+else
+SYS_CFLAGS = $(X11_CFLAGS)
+SYS_LDFLAGS = $(X11_LDFLAGS)
+endif