bug#7952: 24.0.50; crash in find_interval

[Chong Yidong]

Romain Francoise <romain@orebokech.com> writes:

> 1) Start ./src/emacs -Q -nw in the top-level of the source tree
> 2) Do M-x grep-find RET emacs RET
> 3) Do C-x 0 to maximize the window with the *grep* buffer
> 4) Move around with C-v, M-v, M-< or M-> until it crashes (e.g. M-> M-v)

I can reproduce it too, and have bisected the crash down to

103013: Stefan Monnier 2011-01-28 [merge]
 * progmodes/compile.el: Don't use font-lock any more.
  revno: 103013 [merge]
  committer: Stefan Monnier <monnier@iro.umontreal.ca>
  branch nick: trunk
  timestamp: Fri 2011-01-28 17:12:05 -0500
  message:
  * progmodes/compile.el: Don't use font-lock any more.

Unfortunately, this is a change in only compile.el, which means the
problem somewhere in the C code did not originate in this commit, and is
only triggered by it.