[release-branch.go1.20] cmd/compile: use absolute file name in isCgo check
For #23672
Updates #63211
Fixes #63213
Fixes CVE-2023-39323
Change-Id: I4586a69e1b2560036afec29d53e53cf25e6c7352
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/
2032884
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Roland Shoemaker <bracewell@google.com>
(cherry picked from commit
9b19e751918dd218035811b1ef83a8c2693b864a)
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/
2037629
Reviewed-by: Tatiana Bradley <tatianabradley@google.com>
Run-TryBot: Roland Shoemaker <bracewell@google.com>
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/533195
Auto-Submit: Michael Pratt <mpratt@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Bypass: Michael Pratt <mpratt@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>