Mangling of C++0x literal operator functions

[Sean Hunt]

Hello,

I've been working on putting C++0x literal operator functions into 
clang, and I ran into the fact that I wasn't sure how to mangle them. I 
opted for "ul" (for "user literal") followed by an identifier as an 
<operator-name>, but I don't think this is necessarily the best 
solution, because it might cause confusion with vendor-specific types 
(though it's guaranteed not to collide directly). Perhaps "lo" (for 
"literal operator") would be better. It's not a big deal; the user 
literal support (and clang itself) are far from mature enough that a 
minor ABI change would be an issue, but it would nonetheless be best to 
resolve this as soon as possible.

Thanks,

Sean Hunt