bug#20628: 25.0.50; Incorrect line height for some fonts

[Oleh Krehel <ohwoeowho@gmail.com>]

Clément Pit--Claudel <clement.pitclaudel@live.com> writes:

> The patch partially solves the problem for me, but I noticed a few
> problems after running (set-frame-font "Latin Modern Math")
> * When the cursor is at the end of the file, on an empty line, it has a very height.
> * The modeline is still very tall
> * The fix seems to only apply to certain characters. The line that I
> mentioned in my original email, in particular, is still very tall. In
> other words, when trying the following three lines in a Latin Modern
> Math buffer, the last line is much too tall:
>
> 𝓝  ;; This is still very tall
> ∏∑∫ ;; This is a bit taller than the normal height, which is great
> ABC ;; This has the normal height, which is also great

Same issues for me on Ubuntu. The most outstanding one is the mode line
height (of 7 lines instead of 1). And the cursor at eof is very tall as
well.

Additionally, these chars are bad: \\|, λ.
And all lines in Buffer-menu-mode are super-tall, just like the mode
line. And the header line is tall.

Oleh