Windows build broken again: urgent

Alas. Alack. The Windows build is broken again. This time it's pretty fundamental: the stage2 compiler seg-faults every time it invokes the linker: * On GHCi startup * On every Template Haskell splice I don't know when this started, but I did a successful build at 23.10 on 24 November, so it's during the last week. I would gladly do any experiments if someone tells me what to do. It would be really good to fix this. At the moment I'm pretty much stalled on laptop work. Simon