TC: void fnsplit( const char *path, char *drive, char *dir,
			    char *name, char *ext)

	- prototype in dir.h

	- splits a file name from path into drive, dir, name, and ext
	- dir can include subdirectories
	- maximum sizes for these strings are:

	  MAXPATH  80	path
	  MAXDRIVE  3	drive - includes colon (:)
	  MAXDIR   66	dir - includes leading/traing backslashes
	  MAXFILE   9	name
	  MAXEXT    5	ext, including leading dot (.)

	- invertible with fnmerge()