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

[Oleh Krehel]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>>> Any special character you see look bad, please make sure with "C-u C-x ="
>>> with which font it's displayed.
>> OK, they are: 0x2228 and 0x03BB.
>
> That's only the char.  C-u C-x = should give you a crapload more info,
> including the actual font being used.

Here's the rest of the info for "lambda" being composed into "lambda":

             position: 14095 of 224875 (6%), column: 4
            character: l (displayed as l) (codepoint 108, #o154, #x6c)
    preferred charset: ascii (ASCII (ISO646 IRV))
code point in charset: 0x6C
               script: latin
               syntax: w        which means: word
             category: .:Base, L:Left-to-right (strong), a:ASCII, l:Latin, 
r:Roman
             to input: type "C-x 8 RET HEX-CODEPOINT" or "C-x 8 RET NAME"
          buffer code: #x6C
            file code: #x6C (encoded by coding system utf-8-unix)
              display: composed to form "lambda" (see below)

Composed with the following character(s) "ambda" by the rule:
        (?λ)
The component character(s) are displayed by these fonts (glyph codes):
 λ: xft:-unknown-Latin Modern 
Math-normal-normal-normal-*-15-*-*-*-*-0-iso10646-1 (#xF6F)
See the variable `reference-point-alist' for the meaning of the rule.

Character code properties: customize what to show
  name: LATIN SMALL LETTER L
  general-category: Ll (Letter, Lowercase)
  decomposition: (108) ('l')

There are text properties here:
  composition          [Show]
  face                 font-lock-keyword-face
  fontified            nil