Patch: Ada. Fix file timestamps (gnatchop -p) for mingw32

[Arnaud Charlet]

> 2003-10-23  Danny Smith  <dannysmith@users.sourceforge.net>
> 
> 	* ada/adaint.c (w32_epoch_offset): Define static const at file
> 	level.
> 	(win32_filetime): Replace offset with w32_epoch_offset. Use NULL
> 	rather than t_create, t_access in call to GetFileTime. Use union
> 	to convert between FILETIME and  unsigned long long.
> 	(__gnat_file_time_name): Test for invalid file handle.
> 	(__gnat_set_filetime_name): Support win32 targets using
> 	w32api SetFileTime.

OK.

Arno