* libio/stdio.h (sys_errlist, sys_nerr, _sys_errlist, _sys_nerr):
Declarations moved to <bits/sys_errlist.h>. Include that file.
* libio/Makefile (headers): Add bits/sys_errlist.h to the list.
* sysdeps/generic/bits/sys_errlist.h: New file. This does *not*
declare sys_errlist and sys_nerr.
* sysdeps/unix/sysv/linux/bits/sys_errlist.h: New file. Does
provide declarations.
