Scramble compatibility, etc.

[Guddler]

Originally reported by @lurkio

This is obviously a deep-rooted emulation issue (or multiple issues), but I thought I’d just flag it up anyway. Feel free to delete or remove this issue-report if you feel it doesn’t belong here.

The WinBeebEm-optimised version of tricky’s Scramble just doesn’t work properly in MacBeebEm -- graphical glitches all over the shop. Reminds me a bit of what happens with White Light in MacBeebEm.

tricky’s Scramble thread: https://stardot.org.uk/forums/viewtopic.php?f=57&t=14988

Mick Brown’s auto-detecting version of Scramble (selects WinBeebEm version automatically): https://stardot.org.uk/forums/viewtopic.php?f=32&t=8270&p=221840#p221840