add make.clean to remoe compiled packages

Makefile

@@ -1,15 +1,20 @@
 .PHONY: all test clean build install
 
 GOFLAGS ?= $(GOFLAGS:)
+ARCH=$(shell ls $(GOPATH)/pkg | head -n 1)
+PKG=$(GOPATH)/pkg/$(ARCH)/github.com/goanywhere
 
 all: test build
 
-build:
+clean:
+	@find $(PKG) -name 'rex.a' -delete
+	@find $(PKG) -name 'rex' -type d -print0|xargs -0 rm -r
+
+build: clean
 	@go get -v ./...
 
-test: build
+test:
 	@go test -v ./...
 
 bench: install
 	@go test -run=NONE -bench=. $(GOFLAGS) ./...
-