Pointers to get started porting a kde app

I want to get Filelight

  http://methylblue.com/filelight/

running on OS X. 

I installed qt, kdesupport and kdelibs from:

  http://mirror.services.wisc.edu/mirrors/apple/kde/

but I can't find any trace of the headers, I've obviously totally missed
something.

Doing lsbom -f kdelibs.pkg/Contents/Archive.bom makes it look like I
should be finding kde stuff in /opt/kde/, but I don't have a /opt/kde
directory.

What's up? Any suggestions?

Thanks,
Sam