Two gnome-libs bugs

["Peter S. Housel" <housel home com>]

First, as of right now program_invocation_name and
program_invocation_short_name are not defined anywhere on FreeBSD systems.
(Is this a a Linuxism?)  support/gnome-argp.c did define these names
previously (if configure found them missing from libc) but it's been removed
from the libgnomesupport makefile.

Second, the check for sendmsg in configure.in fails on my machine because
NULL isn't defined.  The patch below fixes it:

Index: configure.in
===================================================================
RCS file: /cvs/gnome/gnome-libs/configure.in,v
retrieving revision 1.137
diff -u -r1.137 configure.in
--- configure.in 1998/12/15 08:30:17 1.137
+++ configure.in 1998/12/15 16:06:48
@@ -104,6 +104,7 @@
 AC_CHECK_FUNCS(grantpt login utmpxname utmpname setutent)
 AC_MSG_CHECKING([for Unix98 sendmsg])
 AC_TRY_LINK([
+#include <stddef.h>
 #include <sys/types.h>
 #include <sys/socket.h>],[
 struct msghdr hdr;