Not all platforms support priority attribute. I'm moving conditional definition of this attribute to `include/__config`.
Reviewed By: #libc, aaron.ballman
Differential Revision: https://reviews.llvm.org/D91565
`pass_object_size` is our way of enabling `__builtin_object_size` to
produce high quality results without requiring inlining to happen
everywhere.
A link to the design doc for this attribute is available at the
Differential review link below.
Differential Revision: http://reviews.llvm.org/D13263
llvm-svn: 254554