Add some warn() statements to t/bool.t, to try and see why test 2 fails - as reported by one of the cpan-testers. (That done, I received an email from Jean-Louis Morel, with a patch that fixes the issue ... I'll retain t/bool.t in its modified state.)
Patch overload_not, overload_not_equiv and overload_equiv (in MPC.xs) so that NaNs do not get passed on to the MPC comparison functions (as this is something forbidden by the documentation). Thanks to Jean-Louis Morel.