My version of the self-documenting makefile trick. Haven't used this too thoroughly yet so I'm not sure what I think of it but it seems ok so far. It was built for use in a project that doesn't have a meaningful 'all' target. It would probably want the filter changed back to something more like in the original for use in a more normal project.

helpsystem.mk

# Modified version of http://www.cmcrossroads.com/article/self-documenting-makefiles

all:
        @printf -- "$(HELPTGT)\n$(ETCTGT)\n" | column -t -s :

HELPTGT := --- Primary Targets ---
helptgt = $1$(eval $(if $(filter-out $(.DEFAULT_GOAL),$(MAKECMDGOALS)),,HELPTGT+=\n$(subst %,<name>,$1): - $2))

ETCTGT := --- Extra Targets ---
etctgt = $1$(eval $(if $(filter-out $(.DEFAULT_GOAL),$(MAKECMDGOALS)),,ETCTGT+=\n$1: - $2))

# Usage:
# $(call etctgt,clean,Cleans all build products.):
#	@rm -rf build/*
#
# $(call helptgt,build/%.tar.gz,Generate release tarball.): src/%.c src/%.h
#	@tar -czf $@ $^