So we avoid lots of memory allocation.
We can work with char* directly since both the pattern and the file
name are in UTF-8 and there is no need to understand unicode for
such pattern.
(In fact, '?' would not match anyore non-ascii characters, but I
don't think that's a problem. I don't think anyone use '?' in its
exclude list. And the two allocations per call to csync_fnmatch are
really worth getting rid of)
This function only checks the full path and the basename and is thus
around 7x faster. It is very useful in a csync_update context where
we know that the leading dirs have already been checked for exclusion.
