Don't tickle an unreasonable but standard C lib limitation, thank you Vin! src/ChangeLog addition: 2015-03-17 Aidan Kehoe <kehoea@parhasard.net> * data.c (fill_ichar_array): Be a bit more careful never to supply the C library's isupper() with a value outside of that range specified by the C standard. Thank you Vin Shelton for reporting the Linux segmentation violation this provokes, and happy St. Patrick's Day to everyone reading the XEmacs lists!

--- Xmd.h~	Thu Jun 08 23:20:40 1995
+++ Xmd.h	Sun Mar 16 13:09:10 1997
@@ -150,8 +150,9 @@
 typedef CARD16		BITS16;
 typedef CARD8		BYTE;
 
+#ifndef WIN32
 typedef CARD8           BOOL;
-
+#endif