exp/draw: correct Makefile.

Thanks to Allister Macleod

Fixes #112.

R=rsc
CC=golang-dev
https://golang.org/cl/152102

Author: agl

src/pkg/exp/draw/Makefile

@@ -4,7 +4,7 @@
 
 include $(GOROOT)/src/Make.$(GOARCH)
 
-TARG=draw
+TARG=exp/draw
 GOFILES=\
 	arith.go\
 	color.go\