CL 214429, among other things, created gccgo_link_c.txt as a copy of a
test formerly in go_test.go, but accidentally did so incorrectly:
it used -r instead of -n. This was not noticed because the new test
also incorrectly used [gccgo] when it should have used [exec:gccgo].
Fixing both of those, and also fixing the test to use a go.mod file,
revealed that "go build -n -compiler gccgo" doesn't work, because
it passes a non-existent tmpdir to pkgpath.ToSymbolFunc. This CL
fixes that too.
Change-Id: Id89296803b55412af3bd87aab992f32e26dbce0e
Reviewed-on: https://go-review.googlesource.com/c/go/+/341969
Auto-Submit: Ian Lance Taylor <iant@google.com> Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org> Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>