[XML-SIG] Problem with duplicate _main

[George K. Thiruvathukal]

I was using PyXML on MacOS X and ran into this problem of a duplicate
_main entry point (that causes a problem with 'dyld'). I suspect this is a
problem on all platforms but some of the shared object implemenations are
pretty sloppy with duplicate symbols (and warning about them).

The file that I traced the problem to is:
./extensions/expat/xmlwf/xmlwf.c:int tmain(int argc, XML_Char **argv)

George