Implement a new pkg-config safe flag list (containing everything except
for --log-file) and use that when checking flags passed to pkg-config,
instead of using checkCompilerFlags.
Fixes #77387
Change-Id: Id6141d0a2934053aa43e3aa8ce402bd499c4c028
Reviewed-on: https://go-review.googlesource.com/c/go/+/741042
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Pratt <mpratt@google.com>
Auto-Submit: Roland Shoemaker <roland@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>