Thanks Francois-Xavier and Andrew for replying,
That's PR 21766 (appropriately named "Bootstrap failure on i686-pc-cygwin"). Opened almost a month ago. GCC mainline doesn't build on cygwin or mingw since that time.
Seeing that almost no comment had been made by the maintainers on it, and no correct patch proposed, it looks like we're gonna have to live with it for a long time... :(
Ah..., I naively thought that it would have been fixed whilst I was away! What a bloody nuisance.
PS: Detailled info on your problems:
This one is because you're reconfiguring in a non-empty tree. There is a PR number for it, but I don't remember it...
I thought that it was empty; I'l try again. Thanks Paul T
