merged xemacs 21.4.6-r1 Cannot start xemacs. Get segmentations fault. Same with root shell. Same with xemacs 21.1.14 (so called stable release). Would be happy to provide additional info if you tell me what you need.
This is possibly a duplicate of bug 1574.
SANDBOX_DISABLED="1" emerge xemacs did produce for me a working binary
*** This bug has been marked as a duplicate of 1574 ***