RFD: deprecate permissions-related stuff in System.Directory

[Neil Mitchell]

Hi

> 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. Windows increased the number of executable things in
2000 (I think), and its controlled by the environment variable
%PATHEXT%. On my machine:

PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH

i.e. vbs, wsh etc. all are exectuable.

Thanks

Neil