[glib] Fix build on !linux

[Matthias Clasen <matthiasc src gnome org>]

commit 2ad4b2d716220f0ef45bbeb56fb90a7438afa21a
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat May 15 18:15:30 2010 -0400

    Fix build on !linux
    
    Don't define __USE_GNU, thats a glibc-internal macro, and
    don't use SOL_SOCKET when not including sys/socket.h.
    Maybe this file should be called glinuxcredentialsmessage.c...
    
    Bug #618730

 gio/gunixcredentialsmessage.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/gio/gunixcredentialsmessage.c b/gio/gunixcredentialsmessage.c
index 15c4c96..bb4ef00 100644
--- a/gio/gunixcredentialsmessage.c
+++ b/gio/gunixcredentialsmessage.c
@@ -36,7 +36,6 @@
 #ifdef __linux__
 
 #define _GNU_SOURCE
-#define __USE_GNU
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/un.h>
@@ -86,7 +85,11 @@ g_unix_credentials_message_get_size (GSocketControlMessage *message)
 static int
 g_unix_credentials_message_get_level (GSocketControlMessage *message)
 {
+#ifdef __linux__
   return SOL_SOCKET;
+#else
+  return 0;
+#endif
 }
 
 static int