Qalculate, http://qalculate.sourceforge.net/index.html, and its library (libqalculate) are built using glib and GTK+ or KDE for the GUI which are pain in the ass on OS X.
I managed to port the libqalculate library to OS X using Cocoa classes to replace the glib functions and other patches. Everything works except date parsing from a string.
Only OS X >= 10.6 and 64-bit are supported. I can only test on 10.7.4.
I also patched the command line interface of Qalculate, qalc.cc, and i'm working on the native GUI, in Cocoa.
Feel free to contact me
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