Doesn't build on GNU/Hurd with glibc based on libio

[Marcus Brinkmann]

Hi,

the GNU/Hurd platform is switching to a libio based glibc rather than
stdio right now.  So we need the following patch to make it work
(copied and shortened for the relevant cases only from src/s/gnu-linux.h):

(Mmh. Maybe it makes sense to collect all configuration specific to the
GNU C Library that is shared by all platforms supported by the GNU C
Library into a src/s/glibc.h file.)

--- src/s/gnu.h~        Wed Apr 19 07:21:37 2000
+++ src/s/gnu.h Mon Apr 29 16:04:44 2002
@@ -78,3 +78,12 @@
 #endif
 
 #define NARROWPROTO 1
+
+#ifdef emacs
+#include <stdio.h>  /* Get the definition of _IO_STDIO_H.  */
+#if defined(_IO_STDIO_H) || defined(_STDIO_USES_IOSTREAM)
+/* new C libio names */
+#define GNU_LIBRARY_PENDING_OUTPUT_COUNT(FILE) \
+  ((FILE)->_IO_write_ptr - (FILE)->_IO_write_base)
+#endif /* !_IO_STDIO_H */
+#endif /* emacs */