qt5-qtwebengine broken

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Hi!

A commit over the weekend broke qt5-qtwebengine, it now fails to build with:

In file included from ../../3rdparty/chromium/content/browser/appcache/appcache_internals_ui.cc:25:
../../3rdparty/chromium/content/public/browser/browser_context.h:21:10: fatal error: components/spellcheck/spellcheck_buildflags.h: No such file or directory
   21 | #include "components/spellcheck/spellcheck_buildflags.h"
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.

I tried disabling the spellchecking component explicitly (by default
it's enabled) but this is not enough to fix the build, it still
expects the header file to exist.

My last successful build was on April 13.
 Thomas