>> Shouldn't this be fixed in cygwin? While this is an unusual case, it seems reasonable to me that a program should be able to create a new stack if it wants to.

No, it's completely wrong-headed, insane and unreasonable. Your code is 100% bogus and should be taken out the back, lined up against a wall, and machine-gunned.
Then the bleeding corpse should be hung, drawn and quartered.
Then burnt.
Then the smouldering rubble should be jumped up and down on.
By a hippo.
-- Dave Korn, on cygwin mailing list..