Qt 5.8.0 introduced format version 2 for resources embedded into executable,
and now rcc uses this format by default to generate them.
Unfortunately, v2 format includes timestamps for embedded resource files.
Some of resource files (translations) are generated automatically
and have different timestamps for every build.
This means that dash-qt executable is slightly different for every build
because resource data contain different timestamps.
As a result, it makes reproducible build extremely difficult.
Fortunately, Qt 5.9.0 introduced --format-version option for rcc.
This change adds configure check for whether rcc accepts this option
and uses it to force rcc to generate version 1 format data.
Signed-off-by: Oleg Girko <ol@infoserver.lv>
Qt5 is bottled, so configure won't find it without some help. Use
brew to find out its prefix.
Also, qt5 added the host_bins variable to pkg-config, use it.
