Patch for building doc under Windows

[John W. Eaton]

On 25-Oct-2007, Michael Goffioul wrote:

| Hi,
| 
| I'd like to propose the attached patch to solve various problems I've
| always had when building documentation. One part of the patch makes
| use of the correct sepchar to build TEXINPUTS value. The other one
| tries to avoid the use of "--output" argument, because it is not supported
| under MiKTeX.

OK.  Will you please add a comment about this so that later on someone
doesn't find the --output option and try to reverse this change?

| Note: I completely dropped the texi2[dvi|pdf] versions of MSYS or
| GnuWin32, because they do not work well with MiKTeX and switched
| to the texi2dvi provided by MiKTeX; hence the COMSPEC unsetting
| trick should not be needed anymore.

OK, then why to the commands still contain $(UNSETCOMSPEC)?  If that
can be removed, then please also remove its definition.

ChangeLog?

Thanks,

jwe