The xemacs-21.4.22-r4 ebuild breaks when trying to find the X windows mandatory dependency X11/Intrinsic.h. This is because the configure check isn't robust enough to handle deprecation warnings. The deprecation warnings comes from version 2.20 of glibc that warns for use of _BSD_SOURCE and _SVID_SOURCE. Reproducible: Always
A fix is committed. Configure is set to ignore cpp warnings. This has been applied to the xemacs-21.4.24.ebuild as well, the next stable version.