RFC: Changing clang defaults for 3.1

[David Chisnall]

Hi Everyone,

I am considering, for the 3.1 release, making blocks, the non-fragile ABI and 
the non-legacy dispatch mechanism (objc_msgSend(), at least on x86[-64] and 
ARM) the default on FreeBSD, and possibly other platforms.  The old modes will 
still be available, via -fblocks, -fno-objc-nonfragile-abi and 
-fno-objc-nonlegacy-dispatch, but they'll need to be explicitly specified.

Would this break anything for anyone?  Would any other platforms (OpenBSD?) 
like to have the same defaults.  It's probably worth keeping GNU/Linux 
defaulting to the GCC-runtime-compatible mode for everything, at least for now.

David