* changes related to the foreign interface under windows
* changed to understand name mangling imposed by stdcall calling convention
* modified to compile XSB as a dll using foreign functions and a stub executable
Allowed the 5th arg or re_match to unify with the result.
revamped the pattern matching interface
* changes regarding exporting functions under Windows
* updated to understand FOREIGN_WIN32
Changed calling sequence for p_charlist_to_c_string
Added re_subst/6
Changed calling sequence for p_charlist_to_c_string to avoid buffer overruns.
