Be more careful about erroring with probable GNU-syntax keysyms, keymap.c src/ChangeLog addition: 2012-11-06 Aidan Kehoe <kehoea@parhasard.net> * keymap.c (define_key_check_and_coerce_keysym): When worrying about GNU Emacs-like keysym syntax, if the symbol name starts with c-whatever (or s-whatever, or m-whatever), check for a function binding for that before erroring. Otherwise command remapping and C mode interact badly, since most of the C mode commands are regarded as GNU Emacs-style keysyms.