+ifeq ($(USE_SDL),true)
+SYS_CFLAGS = $(SDL_CFLAGS)
+SYS_LDFLAGS = $(SDL_LDFLAGS)
+else
+SYS_CFLAGS = $(X11_CFLAGS)
+SYS_LDFLAGS = $(X11_LDFLAGS)
+endif
+
+INCL = $(SYS_CFLAGS)
+LIBS = $(SYS_LDFLAGS) $(EXTRA_LIBS) -lm
+
+endif # (PLATFORM != dos)
+
+
+ifdef RO_GAME_DIR # path to read-only game data specified
+CONFIG_RO_GAME_DIR = -DRO_GAME_DIR="\"$(RO_GAME_DIR)\""
+endif
+
+ifdef RW_GAME_DIR # path to writable game data specified
+CONFIG_RW_GAME_DIR = -DRW_GAME_DIR="\"$(RW_GAME_DIR)\""
+endif
+
+ifdef SCORE_ENTRIES # number of score entries per player specified