build: Update the build script to make it possible to build for other…

… architectures

This makes it possible to cross-compile cni like so:
$ GOARCH=arm ./build
$ GOARCH=arm64 ./build
$ GOARCH=ppc64le ./build

ref containernetworking#209

build

@@ -10,21 +10,20 @@ if [ ! -h gopath/src/${REPO_PATH} ]; then
 fi
 
 export GO15VENDOREXPERIMENT=1
-export GOBIN=${PWD}/bin
 export GOPATH=${PWD}/gopath
 
 echo "Building API"
 go build "$@" ${REPO_PATH}/libcni
 
 echo "Building reference CLI"
-go install "$@" ${REPO_PATH}/cnitool
+go build -o ${PWD}/bin/cnitool "$@" ${REPO_PATH}/cnitool
 
 echo "Building plugins"
 PLUGINS="plugins/meta/* plugins/main/* plugins/ipam/*"
 for d in $PLUGINS; do
 	if [ -d $d ]; then
 		plugin=$(basename $d)
 		echo "  " $plugin
-		go install "$@" ${REPO_PATH}/$d
+		go build -o ${PWD}/bin/$plugin "$@" ${REPO_PATH}/$d
 	fi
 done

test

@@ -35,7 +35,7 @@ TEST=${split[@]/#/${REPO_PATH}/}
 
 echo -n "Running tests "
 function testrun {
-    sudo -E bash -c "umask 0; PATH=$GOROOT/bin:$GOBIN:$PATH go test -covermode set $@"
+    sudo -E bash -c "umask 0; PATH=$GOROOT/bin:$(pwd)/bin:$PATH go test -covermode set $@"
 }
 if [ ! -z "${COVERALLS}" ]; then
     echo "with coverage profile generation..."