Merge posix_spawn() work with CYGWIN env var switch?

[Cedric Blancher]

Good moring!

Could the posix_spawn() work (branch heads/topic/posix_spawn) be
merged now, but the new version kept off by default unless an option
in the CYGWIN env var is set?

That would make testing IMO much easier...

Ced
-- 
Cedric Blancher <cedric.blancher@gmail.com>
[https://plus.google.com/u/0/+CedricBlancher/]
Institute Pasteur