Since version 24, Emacs supports a generic mode called prog-mode.  Like
all other modes it has its own mode-hook, prog-mode-hook.  For Emacs
users it is common to provide all your generic programming-mode related
customizations in this mode-hook.

cmake-mode is definitely a programming-mode and should support calling
this hook. There are two ways to make that happen:

* Make your major-mode a derived-mode from prog-mode.
* Manually calling the hook upon mode-activation.

Implementing a derived mode may be the most proper thing to do, but that
may require quite a few structural changes.  For now just call the hook
explicitly if it exists.  This should cover much of what users need.