For qt4-qtruby-2.0.3, cmake/modules/FindQwt5.cmake uses a platform specific tool (ldd) to find the qwt libraries.  On
macosx systems, the equivalent to "ldd" is "otool -L".  I changed both occurrences of ``"ldd"''
to ``"otool" "-L"'' and it built OK on macosx 10.4, but that's still platform specific.  Unfortunately,
I don't know cmake well enough to know how to generalize this, but at least it's reported now.

Dave