cmd/go: pass -X64 to ar on aix/ppc64

    
    On aix/ppc64, ar tool must always have -X64 argument if it aims to
    create 64 bits archives.
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/165317

From-SVN: r269404

gcc/go/gofrontend/MERGE

-3ae3024cae07fe7e85968ad2583add350616b296
+14e48e756af205a68374c872f3bd03d62ccd70bb
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

libgo/go/cmd/go/internal/work/gccgo.go

@@ -278,6 +278,13 @@ func (tools gccgoToolchain) link(b *Builder, root *Action, out, importcfg string
 		return nil
 	}
 
+	var arArgs []string
+	if cfg.Goos == "aix" && cfg.Goarch == "ppc64" {
+		// AIX puts both 32-bit and 64-bit objects in the same archive.
+		// Tell the AIX "ar" command to only care about 64-bit objects.
+		arArgs = []string{"-X64"}
+	}
+
 	newID := 0
 	readAndRemoveCgoFlags := func(archive string) (string, error) {
 		newID++
@@ -293,11 +300,11 @@ func (tools gccgoToolchain) link(b *Builder, root *Action, out, importcfg string
 			b.Showcmd("", "ar d %s _cgo_flags", newArchive)
 			return "", nil
 		}
-		err := b.run(root, root.Objdir, desc, nil, tools.ar(), "x", newArchive, "_cgo_flags")
+		err := b.run(root, root.Objdir, desc, nil, tools.ar(), arArgs, "x", newArchive, "_cgo_flags")
 		if err != nil {
 			return "", err
 		}
-		err = b.run(root, ".", desc, nil, tools.ar(), "d", newArchive, "_cgo_flags")
+		err = b.run(root, ".", desc, nil, tools.ar(), arArgs, "d", newArchive, "_cgo_flags")
 		if err != nil {
 			return "", err
 		}
@@ -516,7 +523,7 @@ func (tools gccgoToolchain) link(b *Builder, root *Action, out, importcfg string
 
 	switch buildmode {
 	case "c-archive":
-		if err := b.run(root, ".", desc, nil, tools.ar(), "rc", realOut, out); err != nil {
+		if err := b.run(root, ".", desc, nil, tools.ar(), arArgs, "rc", realOut, out); err != nil {
 			return err
 		}
 	}