Bustage fix, don't enable MOZ_IPC for i386 Mac OS X builds.

configure.in

@@ -5472,6 +5472,9 @@ case "${target}" in
 powerpc-apple-darwin*)
     MOZ_IPC=
     ;;
+i386-apple-darwin*)
+    MOZ_IPC=
+    ;;
 *-wince*)
     MOZ_IPC=
     ;;