fix build: reverting exp/eval Makefile to old form (gofmt doesn't exist when this is built)
fix build: reverting exp/eval Makefile to old form
(gofmt doesn't exist when this is built)

R=rsc
CC=golang-dev
http://codereview.appspot.com/1838041
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go