Merge from gnulib and try to repair bad merge

Merge from gnulib and try to repair bad merge

This attempts to repair problems introduced by the bad merge
5491fd1098d27b3ba3db054076b9ab60fb3558dc.  The easiest way for me
to fix the badly-merged gnulib files was to run
'admin/merge-gnulib', so I did that, which also imported the
following changes:
* build-aux/update-copyright, m4/gnulib.m4:
Update from gnulib, incorporating:
2015-01-15 time: port to MinGW32 3.21
2015-01-15 update-copyright: apply to self
2015-01-11 update-copyright: recognize groff's \(co marker