* It is even more robust now and does not remove the large document
  optimization.
* And actually while problems were caused on NetBSD 10 on ARMv6,
  this likely wasn't a problem on all NetBSD ports and wasn't
  restricted to NetBSD. At the very least Haiku 32-bit was affected
  as well.

It should be more robust now.
The changes on CellBuffer should be reviewed again, though.

* We can use the new SCI_SCROLLVERTICAL instead of SCI_SETFIRSTVISIBLELINE.
* The upgrade will also ease submitting the NetBSD-support patch.

* It requires a forced refresh on startup (even though that should be the
  default). Otherwise, it wouldn't print the info line correctly.
* Redirect stdin and pass it to newterm() to fix key queuing.
  Probably necessary for supporting ncurses on NetBSD as well.
* Avoid doupdate() if screen is too small: fixes crashes for very
  small windows.
* Updated Scintilla: There were some implicit typing assumptions,
  that are broken by this platform.

* pkg-config check for `ncurses` fails if it failed previously for `ncursesw`.
  This is the case e.g. for ncurses from NetBSD's pkgsrc.
* No longer assume that any libncurses is not enhanced (X/Open compatible).
* SciTECO and Scinterm require to find a curses.h in the include paths.
  The ncurses check must therefore not be limited to the first best
  ncurses/ncurses.h and the like.
* We now always check for X/Open compatibility and always require
  a curses.h in the standard directories or as given by pkg-config.
* AX_WITH_CURSES was radically rewritten and is now called AX_WITH_NCURSES.
* --with-interface=netbsd-curses gets its own detection code.
  It always requires a curses.h in the standard paths and a libcurses.
  It should now be fixed for real NetBSD installations if the ncurses
  port is installed as well.
* Unified all of the curses-arguments to CURSES_CFLAGS and CURSES_LIBS.
  There is no reason we need PDCURSES_CFLAGS, XCURSES_CFLAGS etc.

* SCI_COLOR_PAIR() is now a function teco_color_pair() since it also became
  an inline function in Scinterm.

* If the background color would be non-black, render text in reverse
  video. ncurses doesn't do that automatically.
* Fixes rendering under historical terminals like VT100 and VT240,
  but also all of the monochrome versions of modern emulators in terminfo.
* This also improves the situation when $TERM is set to something conservative,
  e.g. when connecting via RS232.
* Scinterm is temporarily changed to my own fork, which already contains
  a monochrome patch.

* see https://github.com/orbitalquark/scinterm/issues/26
* scintilla_wnoutrefresh() actually caused a refresh(), thus updating the physical screen
  before calling teco_curses_info_popup_noutrefresh() and doupdate().
* This was visible when redrawing the both Scintilla view and popup often as happens during
  scrolling or when clicking on the popup borders.
* This was probably broken since v2.1.0.

* Turns out that on SunOS/OmniOS the ncurses port does not ship with
  a ncursesw pkg-config file, but the ncurses file is for a version,
  that does contain widechar support as well.
* Instead of adding yet another recursive PKG_CHECK_MODULES() call,
  we now use the AX_WITH_CURSES() macro, which is probably more robust.
  This should at least fix ./configure on OmniOS.
* It also adds a number of feature C macros, that could be useful to
  check in the future.
* At the moment, we strive to support all X/Open-compatible Curses
  libraries, but both enhanced and color functions are required.
  Therefore plain SVr4 Curses is not supported.
* source: https://www.gnu.org/software/autoconf-archive/ax_with_curses.html