build: allow to build outside the etcd directory

And added gopath hack which allows to build without setting any GOPATH
env. Just run the build script when you have installed golang.

build

@@ -1,5 +1,8 @@
 #!/bin/sh -e
 
+CDIR=$(cd `dirname "$0"` && pwd)
+cd "$CDIR"
+
 # set some environment variables
 ORG_PATH="github.com/coreos"
 REPO_PATH="${ORG_PATH}/etcd"
@@ -35,7 +38,15 @@ etcd_build() {
 	CGO_ENABLED=0 go build $GO_BUILD_FLAGS -installsuffix cgo -ldflags "-s" -o ${out}/etcdctl ${REPO_PATH}/cmd/etcdctl
 }
 
+etcd_setup_gopath() {
+	export GOPATH=${CDIR}/gopath
+	rm -f $GOPATH/src
+	mkdir -p $GOPATH
+	ln -s ${CDIR}/cmd/vendor $GOPATH/src
+}
+
 toggle_failpoints
+etcd_setup_gopath
 
 # don't build when sourced
 (echo "$0" | grep "/build$" > /dev/null) && etcd_build || true

test

@@ -220,12 +220,6 @@ function build_pass {
 	GO_BUILD_FLAGS="-a -v" etcd_build
 }
 
-# Set up gopath so tests use vendored dependencies
-export GOPATH=${PWD}/gopath
-rm -f $GOPATH/src
-mkdir -p $GOPATH
-ln -s ${PWD}/cmd/vendor $GOPATH/src
-
 for pass in $PASSES; do
 	${pass}_pass
 done