Simplify makefile.

Makefile

@@ -1,26 +1,22 @@
 # Use shadowsocks as command prefix to avoid name conflict
 # Maybe ss-local/server is better because easier to type
 PREFIX := shadowsocks
-LOCAL := $(GOBIN)/$(PREFIX)-local
-SERVER := $(GOBIN)/$(PREFIX)-server
+LOCAL := $(GOPATH)/bin/$(PREFIX)-local
+SERVER := $(GOPATH)/bin/$(PREFIX)-server
 CGO := CGO_ENABLED=0
 
-# TODO define the install package path for use in clean and detect whether
-# package need re-build
-
 all: $(LOCAL) $(SERVER) $(TEST)
 
 .PHONY: clean
 
 clean:
-	rm -rf $(LOCAL) $(SERVER) $(TEST)
+	rm -f $(LOCAL) $(SERVER) $(TEST)
 
+# -a option is needed to ensure we disabled CGO
 $(LOCAL): shadowsocks/*.go cmd/$(PREFIX)-local/*.go
-	cd shadowsocks; go install
 	cd cmd/$(PREFIX)-local; $(CGO) go install -a
 
 $(SERVER): shadowsocks/*.go cmd/$(PREFIX)-server/*.go
-	cd shadowsocks; go install
 	cd cmd/$(PREFIX)-server; $(CGO) go install -a
 
 local: $(LOCAL)