Created attachment 3937 
patch for Xfce4-clipman-plugin with clang

Xfce4-clipman-plugin 1.2.2 does not build with clang 3.0-ish (revision 142614),
it warns about cb_check_primary_clipboard not returning a value which gets promoted to an error somewhere by the configure script.

In this function, a g_return_if_fail(arg) should be a g_return_val_if_fail(arg, FALSE)

Build- and run-tested without any side effects.