build, windows: fixed x64 configuration issue

Backported from master 8010bf9
build, windows: do not fail on Windows SDK Prompt

Backported from master 2f6d4b4
process: don't close stdio fds during spawn

This is needed when closed stdio fd is reused for uv_spawn pipe.
Fixes #1211
Merge branch 'v0.10'

Conflicts:
	src/unix/process.c
unix: fallback to blocking writes if reopening a tty fails

In case reopening the file descriptor fails, fallback to the old
behavior where we do blocking writes, to avoid disrupting other
processes potentially using the file descriptor.