A skeleton Makefile.

Makefile

.DEFAULT_GOAL = targets

# List available targets.
.PHONY: targets
targets:
	@echo Available targets are:
	@echo
	@awk -v default_goal=$(.DEFAULT_GOAL) '/^# / { \
		description = substr($$0, 3); \
		line = ""; \
		location = 0; \
		\
		while ((getline line) > 0) { \
			location = match(line, /^[^.:]+/); \
			\
			if (location > 0) { \
				break; \
			} \
		} \
		\
		target = substr(line, RSTART, RLENGTH); \
		\
		if (target == default_goal) { \
			printf "    %-7s    %s \033[1mThis is the default target.\033[0m\n", target, description; \
		} \
		else { \
			printf "    %-7s    %s\n", target, description; \
		} \
		\
	}' $(MAKEFILE_LIST)