dbghelp: Implement SymEnumSourceFilesW.

[Eric Pouech]

> The A version should call the W one, not the other way around.
Alexandre,

in order to properly manage this, we need to move file names in dbghelp 
from ansi to unicode
but, as dbghelp API uses some kind of regular expression to match 
filenames, we need a unicode regex function set
unfortunately, glib doesn't provide this (yet)

so, shall we ?:
- embed a (simple) unicode regex lib in dbghelp
- or make generic in libwine (so that the day that glib provides the 
right interface we can use it)
- or ...

libTRE seems a good choice here, with compatible license

A+

-- 
Eric Pouech
"The problem with designing something completely foolproof is to underestimate the ingenuity of a complete idiot." (Douglas Adams)