Most warnings have been cleaned up:
* min meson version is now 1.0
* additional parameters such as check, recursive added
* uses now global_source_root() instead of source_root()
* catting files on Windows wasn't actually working -- used in unit
tests. This is because meson passes paths with forward slashes to
cmd.exe `type` command, which doesn't understand them. This is bad,
because we were running effectively null tests for the affected tests.
Fortunately, the same tests were configured correctly on macOS and
Linux, and were all passing, so no serious damage.
There is one significant warning left:
`WARNING: Project targets '>=1.0' but uses feature deprecated since
'0.64.0': copy arg in configure_file. Use fs.copyfile instead`
Refer to mesonbuild/meson#12792. I have opened a PR against that to
undeprecate `copy` kwarg in a future version of meson.
Fixes: #8399
Moves variable declaration for `bool enabled` from .h to .cpp and fixes
up builds. Fixes `#include` in ldml_test_source.cpp which was inside a
namespace.
Fixes: #10426
* Enables identification of KMXPlus files in processor factory
* Adds a stub action to generate an 'a' output character
* Adds a passing null_keyboard unit test for a hypothetical ldml
keyboard
