Hi all,

I'm running into an issue with a particular font. I'm not sure if 
this is a problem with Emacs or with the font, so before reporting 
an actual bug, I thought I'd ask here first.

The font I'm having trouble with is Linux Libertine O, which is a 
variable-width font, so it only shows when `variable-pitch-mode` 
is enabled.

The issue occurs with several diacritics of the International 
Phonetic Alphabet[1], which are combining characters. One 
character causing the issue is ̩ COMBINING VERTICAL LINE BELOW 
0x0329. When this character is combined with e.g., n, the result 
is displayed as a (small) capital n with the diacritic, not as an 
lower case n.

The screen show below shows the problem (it's the final letter in 
the word):