Starting to look for a multibyte character not at the start of the string,
but only as far back as such a character can possibly be.
Speedup suggested by Mark Majeres.


git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@5147 35c25a1d-7b9e-4130-9fde-d3aeb78583b8
2 files changed