bug#57207: 29.0.50; Fontification is slow after e7b5912b23 (Improvements to long lines handling)

[Gregory Heytings]

> > Ihor, any chance that you could try the patch (which I attach again to 
> > this post) and tell us if if solves your original problem, namely 
> > fontification that is slowed down in large Org files?
>
> The patch does not appear to apply onto current master.

It does here (at 8d4789c072), both with "git apply" and "patch -p1".  Are 
you sure you're really on the master branch, without local modifications 
in src/buffer.h and src/xdisp.c?