I'm not really happy that this is really a source tarball in any useful way. The "source" tarball packages up the code generated by swig. This is not really source in the sense that a developer could use it to change anything.
I'd expect source to include the swig typemap and whatever other files that swig needs to do the generation, and perhaps the original qpid/messaging.h and other C++ header files .Although for packaging purposes you could have a build dependency on the appropriate -devel package and not include the actual files.
The extra work I think this needs is to make the Cmake tooling now work both standalone and as part of the full build - I'm not sure how good cmake is at that.