All ghc-compiled binaries seg-fault (on Windows)

Bad news. On Windows, every binary built with GHC HEAD (as of today) seg-faults. Even

main = print “Hello”

Thus

/cygdrive/c/tmp$ c:/code/HEAD/inplace/bin/ghc-stage1 Hello.hs 
[1 of 1] Compiling Main             ( Hello.hs, Hello.o )
Linking Hello.exe ...
/cygdrive/c/tmp$ ./Hello
Segmentation fault/access violation in generated code

(And of course including the stage-2 compiler.) This started happening sometime in the last day or two; I don’t know exactly when. This is with a fresh tree, downloaded from the git repo, with config settings for validation.

Might someone look at this? It’s pretty serious!

Simon