cmd: add -maix32 to gcc calls for aix/ppc

As gcc might now be compiled in 64bit, -maix32 must always be added
to ensure that created objects will be 32bit.

Change-Id: I0b87e000c18d4a8a957ac0c36956caed8ed869ea
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/250778
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/libgo/go/cmd/cgo/gcc.go b/libgo/go/cmd/cgo/gcc.go
index 249cfe4..f774cbb 100644
--- a/libgo/go/cmd/cgo/gcc.go
+++ b/libgo/go/cmd/cgo/gcc.go
@@ -1573,6 +1573,10 @@
 		if goos == "aix" {
 			return []string{"-maix64"}
 		}
+	case "ppc":
+		if goos == "aix" {
+			return []string{"-maix32"}
+		}
 	}
 	return nil
 }
@@ -1615,7 +1619,6 @@
 	c = append(c, p.GccOptions...)
 	c = append(c, p.gccMachine()...)
 	if goos == "aix" {
-		c = append(c, "-maix64")
 		c = append(c, "-mcmodel=large")
 	}
 	c = append(c, "-") //read input from standard input
diff --git a/libgo/go/cmd/go/internal/work/exec.go b/libgo/go/cmd/go/internal/work/exec.go
index d610410..65f3011 100644
--- a/libgo/go/cmd/go/internal/work/exec.go
+++ b/libgo/go/cmd/go/internal/work/exec.go
@@ -2503,6 +2503,10 @@
 		if cfg.Goos == "aix" {
 			return []string{"-maix64"}
 		}
+	case "ppc":
+		if cfg.Goos == "aix" {
+			return []string{"-maix32"}
+		}
 	}
 	return nil
 }