silently passes -export-dynamic to the linker, clang doesn't, issues
a warning and discards it. This leads to lots of runtime warnings like
Gtk-WARNING **: Could not find signal handler ...
printed and to misbehaviour of gummi (especially menus don't work).
Problem (including the clang warnings about '-e xport-dynamic') by
Sebastian Neuper.
Some help and hints from jca@.
While this isn't the best way to fix it (because clang still prints
warnings when compiling rather than linking), it just works[tm],
and apart from one newer release of gummi (0.6.6), there's not much
upstream activity.