Add bin/gitlab-sshd as an explicit Makefile target

Since https://gitlab.com/gitlab-org/gitlab-shell/-/merge_requests/682,
Kerberos headers and libraries are needed to build gitlab-sshd.  If
they are not available, `make build` successfully compiles
`bin/gitlab-shell` but fails to build `bin/gitlab-sshd`. However,
running `make build` again would do nothing and appear to be succeed
because `bin/gitlab-shell` existed. This led to Omnibus GitLab quietly
dropping the `gitlab-sshd` binary, as seen in
https://gitlab.com/gitlab-org/omnibus-gitlab/-/merge_requests/6446#note_1265879416.

To ensure `make build` properly fails if `bin/gitlab-sshd` cannot
be built, we make the binary an explicit build target.

Changelog: changed

Author: stanhu

Makefile

@@ -24,7 +24,7 @@ GOBUILD_FLAGS := -ldflags "-X main.Version=$(VERSION_STRING) -X main.BuildTime=$
 
 PREFIX ?= /usr/local
 
-build: bin/gitlab-shell
+build: bin/gitlab-shell bin/gitlab-sshd
 
 validate: verify test
 
@@ -58,10 +58,13 @@ setup: _script_install bin/gitlab-shell
 _script_install:
 	bin/install
 
-compile: bin/gitlab-shell
+compile: bin/gitlab-shell bin/gitlab-sshd
 bin/gitlab-shell: $(GO_SOURCES)
 	GOBIN="$(CURDIR)/bin" go install $(GOBUILD_FLAGS) ./cmd/...
 
+bin/gitlab-sshd: $(GO_SOURCES)
+	GOBIN="$(CURDIR)/bin" go install $(GOBUILD_FLAGS) ./cmd/gitlab-sshd
+
 check:
 	bin/check