libcroco: Improve copyright headers.
The copyright headers should be unambiguous even if a single file is copied from
the GNU gettext package and used elsewhere. Reported by John Darrington.
* libtextstyle/gnulib-local/lib/libcroco/*: Inline the COPYRIGHT file where
applicable. Add copyright header.
* libtextstyle/gnulib-local/lib/libcroco/libcroco-config.h: Add copyright header.
