[Xastir] GDAL and ImageMagik support for Xastir

[Bill Vodall]

> The Cygwin ImageMagic appears to work.  Last weekend when I did a full clean
> install, all I had to add from sources were GDAL and Shapelib (I think) to
> get all the "ok"'s that I needed.
> 
> I'm about to do another clean install since I had to drop back from W2K to
> 98SE to free up resources on the P133 I'm setting up for my car.  The last
> linking stage wasn't completing despite the 144M of RAM and leaving it go
> all night.  I'll confirm what works and what is needed and then update the
> list.

Thanks David,   I'll add Imagemagic to the dependencies for Xastir and see
if everything compiles and runs.   While I'm at it, I'll see if I can turn on the
other optional libraries.  The big gotch is when they requires libraries that
aren't part of Cygwin.  I suppose I'll have to try adding them to the Xastir
package itself and see how much larger that makes it.

Bill