Possible issue with hurd: Fix abi-tag, following ba90e05

[Adhemerval Zanella]

Hi all,

Since ae20c9a17cd95b6f367209c2a9075587616ceb42 my powerpc builds can not load
older binaries using the new loader, although the make check itself does not
shows regressions.  The main difference is now:

$ cat ./csu/abi-tag.h
#define __ABI_TAG_OS 1
#ifndef __ABI_TAG_VERSION
# define __ABI_TAG_VERSION 0,0,0
#endif

Instead of:

#define __ABI_TAG_OS 0
#ifndef __ABI_TAG_VERSION
# define __ABI_TAG_VERSION 2,0,0
#endif


And it seems be failing loading old binaries on:

elf/dl-load.c

1727             osversion = (abi_note[5] & 0xff) * 65536
1728                         + (abi_note[6] & 0xff) * 256
1729                         + (abi_note[7] & 0xff);
1730             if (abi_note[4] != __ABI_TAG_OS
1731                 || (GLRO(dl_osversion) && GLRO(dl_osversion) < osversion))
1732               {
1733               close_and_out:
1734                 __close (fd);
1735                 __set_errno (ENOENT);
1736                 fd = -1;
1737               }