I can't speak to integration with windriver or labview, but we use Git. I love it. We used it last year.
http://code.google.com/p/msysgit/
It has a GUI that works on windows now. =)
I don't see the point in having it integrated with the environment, so I think your first two bullets are not applicable ;-). After I'm done and have closed labview I just double click the git shortcut for the repo I have on my desktop and I commit it. If I'm at home I can push it up to my server.
I very strongly recommend Git. I really love how it handles being completely decentralized.