Generate mashals during build in libxfcegui4

[Brian J. Tarricone]

Nick Schermer wrote:
> Should, with the patch below, also the verinfo number be changed or
> the package version raised? Although I guess nobody used the
> netk-marshal functions, they are not public available anymore.
> 
> http://foo-projects.org/~nick/patches/xfcegui4-marshals.patch
> 
> Everything runs fine here, be I'm not entirely sure. So please sign-off ;-).

Technically, yes (why the hell are the header files even installed?!), 
but I think the 'p_' prefix is clear enough that they were private...

	-brian