c-mode-menu is a compiled Lisp function in `cc-mode.el'.

(c-mode-menu MODESTR)

Return a menu spec suitable for `easy-menu-define' that is exactly
like the C mode menu except that the menu bar item name is MODESTR
instead of "C".

This function is provided for compatibility only; derived modes should
preferably use the `c-mode-menu' language constant directly.