OS X compatibility

[candera]

This doesn't fix everything. zerkenv module1 module2 still chokes. But it basically works. I have this in my .bashrc, since the same problem this patch fixes means you can't do . <(zerkenv -i bash).

    ZERKENV_SH_TEMP=$(mktemp)
    zerkenv -i bash > $ZERKENV_SH_TEMP
    source $ZERKENV_SH_TEMP
    rm $ZERKENV_SH_TEMP

[daveyarwood]

This looks good to me -- seems like in general, we can use a tempfile instead of using the . <(do a thing) syntax.

I think it would be worth making it clear in the README that you may need to do what you ended up doing in your bashrc if you're on OS X. There is an OS X troubleshooting section that might be a good place, maybe with a little footnote linking to it in the place where we advise putting . <(zerkenv -i bash) in your bashrc.