…r 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 #60514
Fixes CVE-2023-29405

Change-Id: I36b6e188a44c80d7b9573efa577c386770bd2ba3
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/+/1902228
Run-TryBot: Roland Shoemaker <bracewell@google.com>
TryBot-Result: Security TryBots <security-trybots@go-security-trybots.iam.gserviceaccount.com>
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1904345
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/501220
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: David Chase <drchase@google.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>

For #60306
For #60514

Change-Id: I3f5d14aee7d7195030e8872e42b1d97aa11d3582
Reviewed-on: https://go-review.googlesource.com/c/go/+/501298
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

… aix/ppc64

The gccgo on the builder is not updated to support runtime/cgo

For #60306.
For #60514.

Change-Id: If0fb1ccdf589cc9741f6a065bacfa4f06e64ec15
Reviewed-on: https://go-review.googlesource.com/c/go/+/501435
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Benny Siegert <bsiegert@gmail.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
(cherry picked from commit 688d75b)
Reviewed-on: https://go-review.googlesource.com/c/go/+/505595
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>