bug#19023: 24.4; Long pause when evaluating numeric expression

[Gareth Rees]

> My crystal ball says that this pause is due to Emacs trying to locate
> a font that can display a character whose codepoint is U+F4240.  In
> which case, the pause is not n Emacs, it is in system libraries that
> search the available fonts.

That was my guess too, and if I was hoping to see a character at that code 
point, I would have to be prepared to wait for the system to search all the 
fonts to find it.

But normally when I evaluate a numeric expression, I do not want to see a 
character—I’m just using M-: as a calculator—and so the wait is unnecessary 
(and a regression from 24.3).