[m-dev.] diff: changes to runtime startup/termination code

[Bert Thompson]

|Hi,
|
|Bert, this change is based in part on your suggestions from a while back,
|so could you please review this one?

Fergus,

Sorry, I just read this now. 8^(

It's been a while since I last read mercury-developers. I'll read this
diff and also look at the changes Tyson and Tom are making. These
other changes will have quite some impact on what I'm doing, in
particular make it harder. 8^)

Bert

[Diff deleted. I'm reading through it now.]

P.S. I've CC'ed to m-dev. It's worth people knowing that there'll be
even more contention in the runtime.