Comment 18 for bug 425202

Additional information re OS X:
If I copy the code block for Windows in 'inkex.py', change the condition for the platform to match 'darwin', and then launch the command line version with explicitly setting 'INKSCAPE_LOCALEDIR' to the '${prefix}/share/locale' of the current local build/installation, translation of messages returned from python scripts does work.

However, AFAIU it should not be required for a normal "linux-style" configured and installed version of Inkscape to depend on this variable which originally was introduced for packaging only (where the location of the locale files might not be in the same as the compiled-in absolute paths based on ${prefix} used with './configure', and change if the packaged version is self-contained and relocatable).