Fix Windows support in .vendor-helpers.sh

Signed-off-by: Andrew "Tianon" Page <admwiggin@gmail.com>

hack/.vendor-helpers.sh

@@ -5,10 +5,18 @@ PROJECT=github.com/docker/docker
 # Downloads dependencies into vendor/ directory
 mkdir -p vendor
 
-rm -rf .gopath
-mkdir -p .gopath/src/github.com/docker
-ln -sf ../../../.. .gopath/src/${PROJECT}
-export GOPATH="${PWD}/.gopath:${PWD}/vendor"
+if ! go list github.com/docker/docker/docker &> /dev/null; then
+	rm -rf .gopath
+	mkdir -p .gopath/src/github.com/docker
+	ln -sf ../../../.. .gopath/src/${PROJECT}
+	export GOPATH="${PWD}/.gopath:${PWD}/vendor"
+fi
+export GOPATH="$GOPATH:${PWD}/vendor"
+
+find='find'
+if [ "$(go env GOHOSTOS)" = 'windows' ]; then
+	find='/usr/bin/find'
+fi
 
 clone() {
 	local vcs="$1"
@@ -116,15 +124,15 @@ clean() {
 		findArgs+=( -path "vendor/src/$import" )
 	done
 	local IFS=$'\n'
-	local prune=( $(find vendor -depth -type d -not '(' "${findArgs[@]}" ')') )
+	local prune=( $($find vendor -depth -type d -not '(' "${findArgs[@]}" ')') )
 	unset IFS
 	for dir in "${prune[@]}"; do
-		find "$dir" -maxdepth 1 -not -type d -not -name 'LICENSE*' -not -name 'COPYING*' -exec rm -v -f '{}' +
+		$find "$dir" -maxdepth 1 -not -type d -not -name 'LICENSE*' -not -name 'COPYING*' -exec rm -v -f '{}' ';'
 		rmdir "$dir" 2>/dev/null || true
 	done
 
 	echo -n 'pruning unused files, '
-	find vendor -type f -name '*_test.go' -exec rm -v '{}' +
+	$find vendor -type f -name '*_test.go' -exec rm -v '{}' ';'
 
 	echo done
 }
@@ -136,5 +144,5 @@ fix_rewritten_imports () {
        local target="vendor/src/$pkg"
 
        echo "$pkg: fixing rewritten imports"
-       find "$target" -name \*.go -exec sed -i -e "s|\"${remove}|\"|g" {} \;
+       $find "$target" -name \*.go -exec sed -i -e "s|\"${remove}|\"|g" {} \;
 }