hack: move build opts to the dockerfile

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

hack/build

@@ -1,17 +0,0 @@
-#!/usr/bin/env sh
-
-set -e
-
-: "${DESTDIR=./bin/build}"
-: "${PACKAGE=github.com/docker/buildx}"
-: "${VERSION=$(./hack/git-meta version)}"
-: "${REVISION=$(./hack/git-meta revision)}"
-
-: "${CGO_ENABLED=0}"
-: "${GO_PKG=github.com/docker/buildx}"
-: "${GO_EXTRA_FLAGS=}"
-: "${GO_LDFLAGS=-X ${GO_PKG}/version.Version=${VERSION} -X ${GO_PKG}/version.Revision=${REVISION} -X ${GO_PKG}/version.Package=${PACKAGE}}"
-: "${GO_EXTRA_LDFLAGS=}"
-
-set -x
-CGO_ENABLED=$CGO_ENABLED go build -mod vendor -trimpath ${GO_EXTRA_FLAGS} -ldflags "${GO_LDFLAGS} ${GO_EXTRA_LDFLAGS}" -o "${DESTDIR}/docker-buildx" ./cmd/buildx

hack/git-meta

@@ -1,16 +0,0 @@
-#!/usr/bin/env sh
-
-set -e
-
-case $1 in
-  "version")
-    git describe --match 'v[0-9]*' --dirty='.m' --always --tags
-    ;;
-  "revision")
-    echo "$(git rev-parse HEAD)$(if ! git diff --no-ext-diff --quiet --exit-code; then echo .m; fi)"
-    ;;
-  *)
-    echo "usage: ./hack/git-meta <version|revision>"
-    exit 1
-    ;;
-esac