weird SWIG syntax error with "inline" keyword

[Mark Jenkins]

> Gnucash currently requires only swig 1.3.28. We either need to upgrade this 
> (on trunk) to 1.3.31 or we need to add a workaround for versions lower than 
> 1.3.31, which would mean adding "-Dinline=" to SWIG_PYTHON_OPT.

Given that it was released in November 2006, I think it is old enough to
not be an unreasonable burden for developers to have to obtain.

If swig were a build dependency for people trying to compile the
tarball, it would be a problem, as current distros like Debian
4.0/stable/etch ship 1.3.29.

I also worry that the -Dinline approach could come back to haunt us if
the word inline was to appear in a header where it wasn't simply an
ignorable C keyword, eg; int inline_skating_shoes();, though I'll
concede this seems unlikely.



Mark