sysdep.h:stpcpy change caused build error in autotester

[Hans-Peter Nilsson]

> Date: Wed, 4 May 2005 19:32:27 -0400
> From: Daniel Jacobowitz <drow@false.org>

> See my other message about -D_GNU_SOURCE (which was used).  __USE_GNU
> is internal.

Ah, right that's the one.  No wonder I didn't find it. :-)

> I think your patch is probably wrong, though harmless.

No, not if the intention is to deal with buggy system headers!

brgds, H-P