about the exa patches

[Maarten Maathuis]

Found a potential bug in exaValidateGC, which should be fixed now.

I hope the changes are coming to an end. I still need to know if there
are any external users of fbDoCopy that would care for a wrapper. I'm
assuming that functions that changed their return value from void to
Bool pose no issue, but you're welcome to explain if it's not.

@MrCooper: the approach of patch 8 and 9 is ok by you?

Maarten.