bug#10652: 24.0.93; font-lock very slow for C++

[Chong Yidong]

Helmut Eller <eller.helmut@gmail.com> writes:

> Font lock is extremely slow in this file:
>
> http://hg.openjdk.java.net/jdk7/jdk7/hotspot/raw-file/b92c45f2bc75/src/share/vm/runtime/globals.hpp
>
> Download the file and open it with emacs -Q globals.hpp.  Then
> scroll around in the file to see how slow it is.

I got Emacs into an uninterruptible loop while scrolling through the
buffer :-(

Looks like a regression against Emacs 23's CC mode, which handles the
file just fine.  Alan, could you investigate?  Thanks.