Merge from gnulib.

Merge from gnulib.

This incorporates:
2013-01-04 stdio: remove now-unnecessary stdio.c
2013-01-04 fprintftime: depend on stdio, not ignore-value
2013-01-04 fwrite: silence __wur only for older glibc versions
2013-01-04 fwrite: silence __wur without using inline
* lib/stdio.c: Remove.
* lib/stdio.in.h, lib/strftime.c: Update from gnulib.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.