Protect setting loading with a lock
Protect setting loading with a lock

There is at least a potential race on the %settings_loaded hash,
and who knows inside of that block of code.  Sadly, not enough to
fix #1920, but it seems to now succeed more often, or *hang* more
often.

labster/rakudo,salortiz/rakudo,tbrowder/rakudo,rakudo/rakudo,labster/rakudo,rakudo/rakudo,MasterDuke17/rakudo,labster/rakudo,MasterDuke17/rakudo,salortiz/rakudo,salortiz/rakudo,rakudo/rakudo,MasterDuke17/rakudo,MasterDuke17/rakudo,labster/rakudo,tbrowder/rakudo,tbrowder/rakudo,rakudo/rakudo,salortiz/rakudo,tbrowder/rakudo,tbrowder/rakudo,labster/rakudo,labster/rakudo,rakudo/rakudo,MasterDuke17/rakudo,salortiz/rakudo,tbrowder/rakudo,rakudo/rakudo,MasterDuke17/rakudo,salortiz/rakudo