initial frontend support

Makefile

@@ -23,7 +23,7 @@ endif
 # recursive make considered useful for m-p
 MAKE += -r --no-print-directory
 
-DIRECT_TARGETS := clean distclean check help
+DIRECT_TARGETS := clean distclean check help help/distro help/ve
 .PHONY: $(DIRECT_TARGETS)
 $(DIRECT_TARGETS):
 	@$(MAKE) -f main.mk $@

lib/clean.mk

@@ -53,7 +53,7 @@ distclean: clean
 # than BUILDDIR is -- usually it's unneeded afterwards so just zap it
 postclean: build-image
 	@{ \
-	if [ "$(NUM_TARGETS)" -gt 1 -a -z "$(DEBUG)" ] || \
+	if [ "$(NUM_TARGETS)" -gt 1 -a -z "$(DEBUG)" -a -z "$(__frontend)" ] ||\
 	    [ ! -L "$(SYMLINK)" -a "0$(DEBUG)" -lt 2 ]; then \
 		echo "$(TIME) cleaning up after build"; \
 		$(MAKE) -C "$(BUILDDIR)" distclean \

lib/help.mk

 # this makefile holds the most helpful bits for the toplevel one
 
+ifdef __frontend
+define help_body
+	@for i in $(2); do echo $$i; done
+endef
+else
+define help_body
+	@echo '** available $(1) targets:'; \
+	columnize $(2)
+endef
+endif
+
+help = $(and $(2),$(help_body))
+
 help/distro:
-	@echo '** available distribution targets:'; \
-	columnize $(sort $(DISTROS:distro/%=%))
+	$(call help,distribution,$(sort $(DISTROS:distro/%=%)))
 
 help/ve:
 	@echo '** available virtual environment targets:'; \