fix windows test run
unit test round 2
attempting to fix ccache use on darwin
made ccache optional, no longer pulls clang on darwin build
fixing darwin build from Dockerfile
fixed missing nproc on OSX
updated readme to include regtest example, build examples
fix QT unit tests
made -j get passed down, added build.sh
This contains significant rebase / merge / testing work by Naut
<lbrynaut@protonmail.com>, Anthony Fieroni <bvbfan@abv.bg> and Brannon
King <countprimes@gmail.com>.
Qt's configure grabs the path to xkb's data root during configure, but the
build changes in 5.8 apparently broke the handling for cross builds. As a
result, the string embedded in the binary depends on whether or not some files
are present in the builder's filesystem.
The "-xkb-config-root" configure setting is intended to allow manual overriding
but it is also broken. See: https://bugreports.qt.io/browse/QTBUG-60005
This has since been fixed upstream, so just hard-code the path for now. We can
drop this patch when we bump to a fixed Qt.
Also, fix the "-qt-xkbcommon-x11" config param which was renamed. This does not
appear to affect build results, presumably because auto-detection is working,
but it does not hurt to be explicit.
Github-Pull: #14000
Rebased-From: de0b4fba2f
