Fix build problems with AGG/SVG

[theduckylittle]

Code needs updated to allow AGG/SVG to be chosen by the user:

• IFDEF the SVG Code
• Add appropriate autoconf flags
• Rebuild configure
• Add nmake.opt flags for Windows

[theduckylittle]

sdlime reported that without linking to GDAL, the -lexpat requirement was not met. I've added the checks to the configure scripts to support detecting whether -lexpat is necessary.

[nsavard]

I have a problem building mapserver r9907 related to missing expat dependency. It is not included through gdal automatically.

error: renderers/agg/src/agg_svg_parser.cpp:24:19: error: expat.h: No such file or dire

[nsavard]

RE #comment:3

Notice that I'm building MapServer with FGS and that expat is not installed on my system. Expat is present in $FGS_DEV_HOME/built directory.

[dmorissette]

In r9874 (comment:2), theduckylittle's added a --with-agg-svg-symbols[=yes/no] configure switch, but there was a little bug: if the option was not provided at all, a yes was assumed. I just fixed it in r9908 to go the other way around: do not assume a yes unless explicitly requested (also did a bit a cleanup while I was at it).

Note that before we can call this ticket fixed we need to provide a --with-expat switch to allow specifying the location of the expat lib if it's not in the default system dirs.

[theduckylittle]

I set it to default itself in the same way as AGG. C'est la vie.

danmo, did you want to add the --with-expat or did you want me to do it? I might have some time tonight...

[dmorissette]

Since the SVG symbol stuff comes with a dependency we couldn't enable it by default, unless that dependency is checked and met first.

Please go ahead with the --with-expath switch if you have time, I don't think I'd have time in the near future anyway