gnustep-back font display broken on cairo

[Riccardo Mottola]

Hi all,

I noticed that since commit of 19 May:
Merge pull request #5 from Deek/deek


Font system revamp

font display is broken on certain systems.
Character spacing is broken, characters show excessive spacing between 
them or between words. Cursor placement may be wrong relative to the 
displayed characters!
Even selecting the

Some information
- I was able to reproduce this on Devuan/amd64 and Ubuntu/i386
- Certain system are not affected. FreeBSD/i386 appears to work fine for 
me!
- Certain fonts are more affected than other
- user interface, different applications are affected, it is perfectly 
reproduceable inside Ink
- it must be related to certain character sequences and/or ligatures

I already tried some debugging with Fred.
I tried disabling back-art-subpixel-text and GSFontHinting (I did not 
have any defaults, but even made a skip in the code) with no success.

Any further ideas? Anybody else can reproduce this issue?

The patch is big, and the error is bad... it might need a revert.

Riccardo