cmd/link: work around dsymutils not cleaning temp file

Some versions of dsymutils, notably the one in clang 14.0.3, which
is shipped in some versions of Xcode, have a bug that it creates a
temporary directory but doesn't clean it up at exit. The temporary
directory is created in DSYMUTIL_REPRODUCER_PATH (if set,
otherwise TMPDIR). Work around the issue by setting
DSYMUTIL_REPRODUCER_PATH to the linker's temporary directory, so
the linker will clean it up at exit anyway.

Fixes #59026.

Change-Id: Ie3e90a2d6a01f90040dc2eac91e8e536ccdda5a2
Reviewed-on: https://go-review.googlesource.com/c/go/+/490818
Reviewed-by: Than McIntosh <thanm@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Cherry Mui <cherryyz@google.com>

src/cmd/link/internal/ld/lib.go

@@ -1905,7 +1905,11 @@ func (ctxt *Link) hostlink() {
 		stripCmd := strings.TrimSuffix(string(out), "\n")
 
 		dsym := filepath.Join(*flagTmpdir, "go.dwarf")
-		if out, err := exec.Command(dsymutilCmd, "-f", *flagOutfile, "-o", dsym).CombinedOutput(); err != nil {
+		cmd := exec.Command(dsymutilCmd, "-f", *flagOutfile, "-o", dsym)
+		// dsymutil may not clean up its temp directory at exit.
+		// Set DSYMUTIL_REPRODUCER_PATH to work around. see issue 59026.
+		cmd.Env = append(os.Environ(), "DSYMUTIL_REPRODUCER_PATH="+*flagTmpdir)
+		if out, err := cmd.CombinedOutput(); err != nil {
 			Exitf("%s: running dsymutil failed: %v\n%s", os.Args[0], err, out)
 		}
 		// Remove STAB (symbolic debugging) symbols after we are done with them (by dsymutil).