leave output files for cubemaps

Makefile

@@ -148,6 +148,7 @@ maps/%.bsp: %.bsp
 		"'$(GAME_DIR)$(GAME)'" -allowdebug $(VBIN_FLAGS) $(GAME_FLAGS) $(GAME_TTT_FLAGS) +sv_cheats 1 \
 		+mat_specular 0 +map cubeldr
 	rm -v "$(MOD_DIR)/maps/cubeldr.bsp"
+	touch $@
 
 %.cubehdr: %.bsp %.cubeldr
 	ln -f "$(word 1, $^)" "$(MOD_DIR)/maps/cubehdr.bsp"
@@ -156,6 +157,7 @@ maps/%.bsp: %.bsp
 		"'$(GAME_DIR)$(GAME)'" -allowdebug $(VBIN_FLAGS) $(GAME_FLAGS) $(GAME_TTT_FLAGS) \
 		+sv_cheats 0  +mat_hdr_level 2 +sv_cheats 1 +map cubehdr
 	rm -v "$(MOD_DIR)/maps/cubehdr.bsp"
+	touch $@
 
 	# settle physics
 %.setphys: %.bsp