build: simplify clean.bash
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4257045
diff --git a/src/clean.bash b/src/clean.bash
index 5c1dded..7969e2c 100755
--- a/src/clean.bash
+++ b/src/clean.bash
@@ -22,11 +22,6 @@
for i in lib9 libbio libmach cmd pkg \
../misc/cgo/gmp ../misc/cgo/stdio \
../test/bench ../test/garbage
-do(
- cd "$GOROOT"/src/$i || exit 1
- if test -f clean.bash; then
- bash clean.bash --gomake $MAKE
- else
- $MAKE clean
- fi
-)done
+do
+ gomake -C "$GOROOT/src/$i" clean
+done
