[20.10] use GO_LDFLAGS instead of LDFLAGS to prevent inheriting unrelated options

[thaJeztah]

⚠️ This is a partial / modified cherry-pick of #3513 - the code in the 20.10 branch is different, so I had to do a "find and replace" after resolving conflicts and cherry-picking.

When building on Fedora 36, the build failed. I suspect this is because the
rpm tools also set LDFLAGS, but with options that cannot be used;

GO_LINKMODE=dynamic
+ ./scripts/build/binary
  /go/src/github.com/docker/cli ~/rpmbuild/BUILD/src
  Building dynamic docker-linux-arm64
  + go build -o build/docker-linux-arm64 -tags ' pkcs11' -ldflags '-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -Wl,--build-id=sha1 -Wl,-dT,/root/rpmbuild/BUILD/src/.package_note-docker-ce-cli-0.0.0.20220330082637.68cad50-0.fc36.aarch64.ld -w -X "github.com/docker/cli/cli/version.GitCommit=68cad50" -X "github.com/docker/cli/cli/version.BuildTime=2022-03-30T20:05:36Z" -X "github.com/docker/cli/cli/version.Version=0.0.0-20220330082637-68cad50" -X "github.com/docker/cli/cli/version.PlatformName=Docker Engine - Community"' -buildmode=pie github.com/docker/cli/cmd/docker
# github.com/docker/cli/cmd/docker
flag provided but not defined: -Wl,-z,relro
usage: link [options] main.o

This patch changes the variable we use to GO_LDFLAGS, taking a similar approach
as containerd, and various other projects using this name: https://grep.app/search?q=GO_LDFLAGS

Signed-off-by: Sebastiaan van Stijn github@gone.nl
(cherry picked from commit 391e6ad)
Signed-off-by: Sebastiaan van Stijn github@gone.nl

- What I did

- How I did it

- How to verify it

- Description for the changelog

- A picture of a cute animal (not mandatory but encouraged)

[thaJeztah]

Ah, dang. Forgot about this one; will have to look into vndr to make it not default to use git:// as protocol; I recall I was looking into that, but never finished.

2022/03/31 09:29:01 Download dependencies
2022/03/31 09:29:02 Starting whole vndr cycle because no package specified
fatal: remote error: 
  The unauthenticated git protocol on port 9418 is no longer supported.
Please see https://github.blog/2021-09-01-improving-git-protocol-security-github/ for more information.
fatal: remote error: 
  The unauthenticated git protocol on port 9418 is no longer supported.
Please see https://github.blog/2021-09-01-improving-git-protocol-security-github/ for more information.
fatal: remote error: 
  The unauthenticated git protocol on port 9418 is no longer supported.
Please see https://github.blog/2021-09-01-improving-git-protocol-security-github/ for more information.
fatal: remote error: 
  The unauthenticated git protocol on port 9418 is no longer supported.
Please see https://github.blog/2021-09-01-improving-git-protocol-security-github/ for more information.
fatal: remote error: 
  The unauthenticated git protocol on port 9418 is no longer supported.
Please see https://github.blog/2021-09-01-improving-git-protocol-security-github/ for more information.
fatal: remote error: 
  The unauthenticated git protocol on port 9418 is no longer supported.
Please see https://github.blog/2021-09-01-improving-git-protocol-security-github/ for more information.

[codecov-commenter]

Codecov Report

Merging #3514 (294094c) into 20.10 (91bab60) will not change coverage.
The diff coverage is n/a.

❗ Current head 294094c differs from pull request most recent head 6f7a931. Consider uploading reports for the commit 6f7a931 to get more accurate results

@@           Coverage Diff           @@
##            20.10    #3514   +/-   ##
=======================================
  Coverage   58.57%   58.57%           
=======================================
  Files         299      299           
  Lines       21457    21457           
=======================================
  Hits        12569    12569           
  Misses       7970     7970           
  Partials      918      918           

[thaJeztah]

Rebased, and dropped the second commit, because vndr wasn't the cause after all; see #3516

[thaJeztah]

@ndeloof @tonistiigi PTAL

[thaJeztah]

This one is not urgent; would love to have others also to have a peek (perhaps @tonistiigi and @tianon); I think this change should be fine, but just in case there could be any reason we must also set LDFLAGS. For example, when searching for LDFLAGS, I also found some occurrences in vendor files, such as

cli/vendor/github.com/miekg/pkcs11/pkcs11.go

Lines 14 to 18 in 1616943

	#cgo windows CFLAGS: -DPACKED_STRUCTURES
	#cgo linux LDFLAGS: -ldl
	#cgo darwin LDFLAGS: -ldl
	#cgo openbsd LDFLAGS: -ldl
	#cgo freebsd LDFLAGS: -ldl

And (honestly) I don't know how those interact (perhaps not at all)

[thaJeztah]

Thanks @tianon !

alright; let's get this one in ❤️