Updated instructions for building subsets of MAME using the SOURCES
option.
Added descriptions for several more "useful" settings.
Bumped documentation version as the build system changes are not in
0.245.
machine/z80scc.cpp: Fixed a cast-to-bool that broke detection of changes
to one register bit.
formats/fsmeta.cpp: Use visitors with variants where it makes sense.
docs: Updated minimum required SDL version to 2.0.6 for all targets,
added note that Python 3 is included with Xcode and updated instructions
for downloading stand-alone Python 3 for macOS.
ksys573.cpp: Don't create an insane number of textures for fghtmn and
pnchman internal artwork.
Tidied another batch of slot machine layouts.
* frontend: Added support for message context to localisations.
* frontend: Added string_view versions of the message lookup functions.
* frontend: Added a few more folder options to the internal UI.
* emu/softlist.cpp: Use more appropriate containers.
* Switched to Python 3 by default - this will become a requirement.
* Updated msgfmt.py for message context support.
* frontend: Show all software item info in the internal UI.
* frontend: Search alternate titles in software selection menu.
* 3rdparty/utf8proc: Updated to v2.6.1 (has several fixes).
* frontend: Added software filters for common info fields.
* frontend: Allow UI manager to hold onto persistent session data.
* frontend: Cache software lists for eight machines.
* frontend: Added support for loading localised system names.
* frontend: Add UI for selecting localised system names.
Update compilingmame.rst
* Changes in macOS section regarding current build requirements
* Added basic info for Apple Silicon to macOS build instructions.
* Added note explaining that view options saved in machine CFG take
precedence over INI/command line.
* Added prerequisites for building HTML documentation under MSYS2 and
Fedora Linux.
* Explicitly mentioned that Ubuntu modifies GCC to enable "fortify
source" by default in the relevant section.
* Removed obsolete reference to glibstdc++6.
* Re-formated compiling guide source (hard wrap at 80 columns,
typographical quotes, code blocks for sample command lines).
-genie.lua: Show GCC ignored attribute warnings, but don't fail for
them.
* Harmonised memory region/share finder/creator APIs.
* Moved .found() to optional object finders.
* Added truth test operator to optional object finders.
* Fixed things that were testing .found() on required object finders.
* Improved Doxygen API documentation.
-dec8.cpp: Moved csilver to its own state class.
-docs: Added some notes about setting up and using MSYS2.
