add indication of support for debugging in version info

[pspencer@…]

when mapserver outputs its version string, it would be very useful to know
whether it has been built with debug support or not.  A simple DEBUG=ON|OFF
would suffice.  It should appear in all version strings from the cgi and
mapscript (and in the WMS/WFS server capabilities too?)

[dmorissette]

We may needmore than just DEBUG=ON|OFF, there may be various debug options down
the road, so I'll try to keep room for that. 

What I'll add for now is DEBUG=MSDEBUG if MapServer was compiled with
-DENABLE_STDERR_DEBUG which enables the msDebug() function to send a bunch of
information to stderr.

[dmorissette]

Fixed, in 4.3 CVS only.

$ ./mapserv -v
MapServer version 4.3 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP
SUPPORTS=PROJ SUPPORTS=FREETYPE SUPPORTS=WMS_SERVER SUPPORTS=WMS_CLIENT
SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT INPUT=EPPL7 INPUT=POSTGIS INPUT=OGR
INPUT=GDAL INPUT=SHAPEFILE DEBUG=MSDEBUG