There is probably bug in PScreen.cc, line 59:
const uint PScreen::MODIFIER_TO_MASK_NUM = sizeof(PScreen::MODIFIER_TO_MASK[0]) / sizeof(PScreen::MODIFIER_TO_MASK);
const uint PScreen::MODIFIER_TO_MASK_NUM = sizeof(PScreen::MODIFIER_TO_MASK) / sizeof(PScreen::MODIFIER_TO_MASK[0]);
Thanks for finding this!
Good catch there, assigning to IOError letting him commit.