# Bitmap tiles
-BTILE_DIRS=wall floor tunnel underground grate
+BTILE_DIRS=wall floor tunnel underground grate exit
BTILE_SRC=$(shell find $(patsubst %, $(VPATH)/bitmap/%, $(BTILE_DIRS)) -name "*.png")
BTILE_PNGS=$(patsubst $(VPATH)/bitmap/%, bunker/%, $(BTILE_SRC))