Here's Looking At You, Child.

sudo make me a sandwich.

#!/usr/bin/make -first
.PHONY: me a sandwich.

EUID=$$EUID

me:
	@touch Makefile

a:
	@touch Makefile

sandwich.: a me
	@[[ ${EUID} -ne 0 ]] && echo "What? Make it yourself." || echo "Okay."