[Bug 53155] msys2 cannot be installed under wine

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=53155

--- Comment #18 from Serge S. Gulin  ---
It seemed to me that the following caused the hang:

```
sed '
     /^ac_cv_env_/b end
     t clear
     :clear
     s/^([^=]*)=(.*[{}].*)$/test ${\1+y} || &/
     t end
     s/^([^=]*)=(.*)$/\1=${\1=\2}/
     :end' >>confcache
```

It is from `autom4te`.

When I kill this sed and еру parent shell, it continues the build. Strange. May
be it can help with some clues what is going on. Again, origin MSYS2 (without
full upgrade) works fine here.