cmd/link: use "CC --print-prog-name" to locate tools
When building for macOS with external linking, we currently use
"xcrun" to invoke "dsymutil" and "strip" tools. That doesn't work
well for cross compilation. Use "CC --print-prog-name" to find the
tool path instead.
Fixes #47316.
Change-Id: Ib30c6494c48bfb6a505dc26fe644ef543d777076
Reviewed-on: https://go-review.googlesource.com/c/go/+/336769
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Than McIntosh <thanm@google.com>