PATCH: _GNU_SOURCE when __GNU__

[Clint Adams <clint@xxxxxxx>]

As far as I can tell, nothing is included up to this point which
define __GLIBC__, so the Hurd wasn't getting the
nanosecond-resolution structs guarded by __USE_MISC
and thus was not able to use them in Src/cond.c.
This has nothing to do with /dev/ptmx.

Here is a band-aid:

Index: Src/system.h
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/system.h,v
retrieving revision 1.53
diff -u -r1.53 system.h
--- Src/system.h	16 Jun 2008 22:50:44 -0000	1.53
+++ Src/system.h	30 May 2009 17:40:43 -0000
@@ -37,7 +37,7 @@
 #endif
 #endif
 
-#if defined(__linux) || defined(__GLIBC__)
+#if defined(__linux) || defined(__GNU__)
 /*
  * Turn on numerous extensions.
  * This is in order to get the functions for manipulating /dev/ptmx.