add build-cross for local cross building

Makefile

@@ -3,4 +3,18 @@ build:
 	CGO_ENABLED=1 go build -mod=vendor -o service main.go
 
 build-static:
-	CGO_ENABLED=1 go build -mod=vendor -tags=embed -o service main.go
+	CGO_ENABLED=1 go build -mod=vendor -tags=embed -o service main.go
+
+build-armhf:
+	GOARCH=arm \
+	ARCH=armhf \
+	DEPS="gcc-arm-linux-gnueabihf libc6-dev-armhf-cross" \
+	PREFIX=arm-linux-gnueabihf \
+	./build-cross.sh
+
+build-arm64:
+	GOARCH=arm64 \
+	ARCH=arm64 \
+	DEPS="gcc-aarch64-linux-gnu libc6-dev-arm64-cross" \
+	PREFIX=aarch64-linux-gnu \
+	./build-cross.sh