* This is still rendered as underlined text.
* It uses a new Scinterm upstream feature, so we can
  switch back to the upstream repo.

It does not change anything functionally, though.

The new wcwidth.c wasn't actually linked in.

This requires enhanced INDIC_STRAIGHTBOX semantics, which are not yet upstream in Scinterm.

* This currently needs a yet unmerged patch, fixing the light colors.
* Scinterm no longer systematically initializes the color pairs, so
  we cannot predict their numbers - instead we initialize color pairs
  on demand and store them in a hash map, very similar to what Scinterm
  does internally.
* Scinterm v5.5 can use arbitrary RGB colors now by automatically
  allocating curses colors and pairs.
  We do not expose this in SciTECO yet, although that would also
  be possible.
  It has to be decided first whether the special predefined colors
  will continue to live in the same namespace along with "true"
  RGB colors.

* It was failing on OpenSUSE Tumbleweed i586 on OBS,
  resulting in duplicate symbols and build errors.
  This was not reproducible with 32-bit builds on OpenSUSE Tumbleweed x86_64.
* Instead of hoping for a compiler warning to be treated as an error,
  we now use a static assertion with a _Generic expression.
* The scintilla submodule has also been updated since Neil was asking to
  update the documentation as well.

* Scintilla had build problems if ptrdiff_t doesn't alias int if it has the
  same storage size (e.g. on NetBSD 10 (armv6)).
* Unfortunately, Neil Hodgson refused to merge my previous Scintilla patches that
  would have fixed the issue at the core.
  See https://groups.google.com/g/scintilla-interest/c/STAv6LgLyCo
* He only agreed to introducing a separate flag to work around the issue
  (`-DPTRDIFF_DOESNT_ALIAS_INT`).
* In order to continue to support all standard C/C++ conforming platforms
  we therefore need a compile-time check to check for the aliasability
  of ptrdiff_t and int.