GNUmakefile: detect ARCH buildx TARGET amd64/arm64

Author: RandyMcMillan

GNUmakefile

@@ -1,3 +1,15 @@
+## detect ARCH for buildx
+ARCH                                   :=$(shell uname -m)
+export ARCH
+ifeq ($(ARCH),x86_64)
+TARGET                                 :=amd64
+export TARGET
+endif
+ifeq ($(ARCH),arm64)
+TARGET                                 :=arm64
+export TARGET
+endif
+
 DOCKER=$(shell which docker)
 export DOCKER
 PWD=$(shell echo `pwd`)
@@ -27,7 +39,7 @@ docker-buildx:## 		docker buildx build sequence
 	@$(DOCKER) buildx ls
 	@$(DOCKER) buildx create --use --name miniscript-buildx || true
 	@$(DOCKER) buildx build -t miniscript --platform linux/arm64,linux/amd64 .
-	@$(DOCKER) buildx build -t miniscript --platform linux/arm64 . --load
+	@$(DOCKER) buildx build -t miniscript --platform linux/$(TARGET) . --load
 docker-miniscript:docker-build## 		docker-miniscript
 	@[[ -z "$(shell file ./miniscript | grep inux)" ]] && echo "not linux" && rm ./miniscript || echo "miniscript is built for linux"
 	@$(DOCKER) run --rm -v $(PWD):/src --publish 80:8080  miniscript sh -c "make install"