[release-branch.go1.19] cmd/go,cmd/cgo: in _cgo_flags use one line per flag
The flags that we recorded in _cgo_flags did not use any quoting,
so a flag containing embedded spaces was mishandled.
Change the _cgo_flags format to put each flag on a separate line.
That is a simple format that does not require any quoting.
As far as I can tell only cmd/go uses _cgo_flags, and it is only
used for gccgo. If this patch doesn't cause any trouble, then
in the next release we can change to only using _cgo_flags for gccgo.
Thanks to Juho Nurminen of Mattermost for reporting this issue.
Updates #60306
Fixes #60513
Fixes CVE-2023-29405
Change-Id: Id738a737ecae47babb34c4b4fc4d65336cf0c0f3
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/
1875094
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Roland Shoemaker <bracewell@google.com>
(cherry picked from commit
bcdfcadd5612212089d958bc352a6f6c90742dcc)
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/
1902227
Run-TryBot: Roland Shoemaker <bracewell@google.com>
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/
1904341
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/501216
Auto-Submit: Michael Knyszek <mknyszek@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Bypass: David Chase <drchase@google.com>