Is the 'diacrit' module still needed?

[Paul Eggert]

Today I updated Coreutils to current Gnulib, and noticed that 
gnulib-tool warned that Gnulib's 'diacrit' module is obsolete. So I 
removed Coreutils's use of 'diacrit', as the only use was something 
obsolete in 'ptx'[1].

Does anyone else use 'diacrit'? If not, I suppose we can remove it from 
Gnulib.

[1] 
https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=a71539e62830927957ddea3ddb7615f68ffcc55b