build: Consistently default to linux/amd64 (argoproj#14146)

Signed-off-by: Josh Soref <jsoref@gmail.com>

Makefile

@@ -9,6 +9,8 @@ GEN_RESOURCES_CLI_NAME=argocd-resources-gen
 HOST_OS:=$(shell go env GOOS)
 HOST_ARCH:=$(shell go env GOARCH)
 
+TARGET_ARCH?=linux/amd64
+
 VERSION=$(shell cat ${CURRENT_DIR}/VERSION)
 BUILD_DATE:=$(if $(BUILD_DATE),$(BUILD_DATE),$(shell date -u +'%Y-%m-%dT%H:%M:%SZ'))
 GIT_COMMIT:=$(if $(GIT_COMMIT),$(GIT_COMMIT),$(shell git rev-parse HEAD))
@@ -283,7 +285,7 @@ controller:
 
 .PHONY: build-ui
 build-ui:
-	DOCKER_BUILDKIT=1 docker build -t argocd-ui --target argocd-ui .
+	DOCKER_BUILDKIT=1 docker build -t argocd-ui --platform=$(TARGET_ARCH) --target argocd-ui .
 	find ./ui/dist -type f -not -name gitkeep -delete
 	docker run -v ${CURRENT_DIR}/ui/dist/app:/tmp/app --rm -t argocd-ui sh -c 'cp -r ./dist/app/* /tmp/app/'
 
@@ -294,18 +296,18 @@ ifeq ($(DEV_IMAGE), true)
 # the dist directory is under .dockerignore.
 IMAGE_TAG="dev-$(shell git describe --always --dirty)"
 image: build-ui
-	DOCKER_BUILDKIT=1 docker build --platform=linux/amd64 -t argocd-base --target argocd-base .
+	DOCKER_BUILDKIT=1 docker build --platform=$(TARGET_ARCH) -t argocd-base --target argocd-base .
 	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 GODEBUG="tarinsecurepath=0,zipinsecurepath=0" go build -v -ldflags '${LDFLAGS}' -o ${DIST_DIR}/argocd ./cmd
 	ln -sfn ${DIST_DIR}/argocd ${DIST_DIR}/argocd-server
 	ln -sfn ${DIST_DIR}/argocd ${DIST_DIR}/argocd-application-controller
 	ln -sfn ${DIST_DIR}/argocd ${DIST_DIR}/argocd-repo-server
 	ln -sfn ${DIST_DIR}/argocd ${DIST_DIR}/argocd-cmp-server
 	ln -sfn ${DIST_DIR}/argocd ${DIST_DIR}/argocd-dex
 	cp Dockerfile.dev dist
-	DOCKER_BUILDKIT=1 docker build --platform=linux/amd64 -t $(IMAGE_PREFIX)argocd:$(IMAGE_TAG) -f dist/Dockerfile.dev dist
+	DOCKER_BUILDKIT=1 docker build --platform=$(TARGET_ARCH) -t $(IMAGE_PREFIX)argocd:$(IMAGE_TAG) -f dist/Dockerfile.dev dist
 else
 image:
-	DOCKER_BUILDKIT=1 docker build -t $(IMAGE_PREFIX)argocd:$(IMAGE_TAG) .
+	DOCKER_BUILDKIT=1 docker build -t $(IMAGE_PREFIX)argocd:$(IMAGE_TAG) --platform=$(TARGET_ARCH) .
 endif
 	@if [ "$(DOCKER_PUSH)" = "true" ] ; then docker push $(IMAGE_PREFIX)argocd:$(IMAGE_TAG) ; fi