[PATCH] Optimized __cxa_guard_{acquire,release,abort} for Linux

[Paolo Carlini]

Hi Jakub,
> Here is the patch together with the configure bits.  For native build
> when neither --{enable,disable}-linux-futex is given the same rules as
> in libgomp configury are used, --enable-linux-futex enables it
> unconditionally (and errors if SYS_futex isn't defined in headers),
> --disable-linux-futex disables it.  For cross only explicit
> --enable-linux-futex will enable it, as we shouldn't do link tests.
>   
Patch looks great to me. I say wait a couple more days for comments, and
then commit it.

Thanks again,
Paolo.