[Distutils] Patches for --compiler option

[Lyle Johnson]

> Thanks -- I'll check it in shortly.  One problem:
>
> >                  extra_args.append ('/IMPLIB:' + implib_dir)
> > +                self.mkpath (os.path.dirname(implib_dir))
> >              # if MSVC
>
> I fixed this bug just before seeing your patch with
>
>                 self.mkpath(implib_dir)
>
> One of us misunderstands what 'implib_dir' is, and since you're the one
> using Windows, it could well be me.  Can you test to see which fix is
> the right one?

The /IMPLIB:name switch to the linker is used to specify the name of an
import library. The variable name "implib_dir" should probably be changed to
"implib_file" because it is the file name of the import library and not a
directory name. Having said that, the correct code snippet is:

	implib_file = os.path.join (self.build_temp, \
	    self.get_ext_libname (extension_name))
	extra_args.append ('/IMPLIB:' + implib_file)
	self.mkpath (os.path.dirname (implib_file))

I just tested this on two of my projects plus PyXML-0.5.4 and it works
properly.

Lyle