Fixing build bustage under VC++

[Ian Roxborough]

Mo DeJong wrote:
> > What are your feelings on VC++ vs gcc for building SN?
> >
> > I'm left with the distinct impression building gcc
> > would be easier, but then again, I'm just talk about
> > compiling, I've yet to get it to run.
> 
> I think we should shoot for getting the VC++ build working again before
> working on further gcc support under Windows. The main point of a
> SN 5.1 release is to get the bug fixes and Tcl/Tk 8.3 upgrade out to
> folks. I don't think that switching the release compiler at the same time
> is such a good idea. Last I remember, the VC++ build was working
> and SN was running (but, that was many moons ago). I seem to
> remember that I had 90% of the packages compiling with mingw, but
> there were a couple (perhaps Tix, db, or grep) that were not yet ported.
> I know that at least Tcl, Tk, Incr Tcl,  and Incr Tk compiled with gcc.

Everything compiles with gcc just now.  There is like one
link error in hyper.exe because the tclstubs library is
missing from the link line.

The runtime problems seem to do with a Tcl_Preserve call
setting the interp pointer to NULL, but I've not tracked
down why.  I think I've seen similar problems with the
gcc compiled wish83, however some thing about Insight's Init
code let's it avoid this problem.

Ian.