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

From: Lars Ingebrigtsen <[email-masked]>
Date: Fri, 19 Aug 2022 18:02:37 +0200

I tried reproducing this on Macos, but it doesn't happen there.  Are
there Linux-specific code paths in this narrowing code?