Make thread names useful in a debugger

Associate the name with the system thread, so that debuggers
can see it. This is currently only implemented for Linux, using
prctl.

https://bugzilla.gnome.org/show_bug.cgi?id=660635

glib/gthread-posix.c

@@ -63,7 +63,9 @@
 #ifdef HAVE_SCHED_H
 #include <sched.h>
 #endif
-
+#ifdef HAVE_SYS_PRCTL_H
+#include <sys/prctl.h>
+#endif
 
 static void
 g_thread_abort (gint         status,
@@ -1047,5 +1049,13 @@ g_system_thread_equal (gpointer thread1,
   return (pthread_equal (*(pthread_t*)thread1, *(pthread_t*)thread2) != 0);
 }
 
+void
+g_system_thread_set_name (const gchar *name)
+{
+#ifdef HAVE_SYS_PRCTL_H
+  prctl (PR_SET_NAME, name, 0, 0, 0, 0);
+#endif
+}
+
 /* {{{1 Epilogue */
 /* vim:set foldmethod=marker: */