RFD: deprecate permissions-related stuff in System.Directory

[Simon Marlow]

Neil Mitchell wrote:
>> returns True for execute permission on Windows, and the one in GHC 6.8.1
>> returns True if the filename ends in something like ".exe" or ".bat" (both
>> are wrong, just wrong in different ways).
> 
> The GHC one is pretty wrong, since ".com" is also a valid extension
> for executables.

Um, I said "something like ...".  The code in fact is Microsoft's 
implementation of stat(), in the CRT.  The list it uses is:

         /* see if file appears to be executable - check extension of name */

         if (p = _tcsrchr(name, _T('.'))) {
             if ( !_tcsicmp(p, _T(".exe")) ||
                  !_tcsicmp(p, _T(".cmd")) ||
                  !_tcsicmp(p, _T(".bat")) ||
                  !_tcsicmp(p, _T(".com")) )
                 uxmode |= _S_IEXEC;
         }


Cheers,
	Simon