Windows: Native make test-unit

Signed-off-by: John Howard <jhoward@microsoft.com>

hack/make/test-unit

@@ -25,7 +25,8 @@ bundle_test_unit() {
 	go test $COVER $GCCGOFLAGS -ldflags "$LDFLAGS" "${BUILDFLAGS[@]}" $TESTFLAGS $pkg_list
 }
 
-if [[ "$(go version)" =~ "gccgo" ]]; then
+
+if [[ "$(go version)" == *"gccgo"* ]]; then
 	GCCGOFLAGS=-gccgoflags="-lpthread"
 else
 	COVER=-cover