makefile: update ldflags and add strip for static builds

This patch
* drops the default `-w` flag for `make static`, which helps with
  debugging the static runc binary;
* adds `EXTRA_LDFLAGS="-w -s"` to `script/release.sh` to disable DWARF
  generation and symbol table for the release runc binary;
* adds strip in `script/release.sh` for a further size-optimized release
  runc binary.

Signed-off-by: Kailun Qin <kailun.qin@intel.com>

Makefile

@@ -23,7 +23,7 @@ endif
 GO_BUILD := $(GO) build -trimpath $(GO_BUILDMODE) $(EXTRA_FLAGS) -tags "$(BUILDTAGS)" \
 	-ldflags "-X main.gitCommit=$(COMMIT) -X main.version=$(VERSION) $(EXTRA_LDFLAGS)"
 GO_BUILD_STATIC := CGO_ENABLED=1 $(GO) build -trimpath $(EXTRA_FLAGS) -tags "$(BUILDTAGS) netgo osusergo" \
-	-ldflags "-w -extldflags -static -X main.gitCommit=$(COMMIT) -X main.version=$(VERSION) $(EXTRA_LDFLAGS)"
+	-ldflags "-extldflags -static -X main.gitCommit=$(COMMIT) -X main.version=$(VERSION) $(EXTRA_LDFLAGS)"
 
 .DEFAULT: runc
 

script/release.sh

@@ -33,6 +33,7 @@ function build_project() {
 	local libseccomp_ver='2.5.1'
 	local tarball="libseccomp-${libseccomp_ver}.tar.gz"
 	local prefix
+	local ldflags="-w -s"
 	prefix="$(mktemp -d)"
 	wget "https://github.com/seccomp/libseccomp/releases/download/v${libseccomp_ver}/${tarball}"{,.asc}
 	tar xf "$tarball"
@@ -46,8 +47,9 @@ function build_project() {
 	# Add -a to go build flags to make sure it links against
 	# the provided libseccomp, not the system one (otherwise
 	# it can reuse cached pkg-config results).
-	make -C "$root" PKG_CONFIG_PATH="${prefix}/lib/pkgconfig" COMMIT_NO= EXTRA_FLAGS="-a" static
+	make -C "$root" PKG_CONFIG_PATH="${prefix}/lib/pkgconfig" COMMIT_NO= EXTRA_FLAGS="-a" EXTRA_LDFLAGS="${ldflags}" static
 	rm -rf "$prefix"
+	strip "$root/$project"
 	mv "$root/$project" "$1"
 }