bug#64204: C/C++ local variables not syntax highlighted if they start with $

[Po Lu]

Eli Zaretskii <eliz@gnu.org> writes:

> Thanks, but shouldn't this be optional behavior, which users should be
> able to control?  Standard C disallows '$' in identifiers AFAIK, and
> some users might wish to follow the Standard.

There is no other use for the character $, so this is not necessary:
it's either an identifier or a syntax error, and we don't try to fontify
syntax errors.