Like we do in libc++, PSTL needs the ability to constrain
ABI-unstable symbols to each translation unit. This is OFF by
default (like for libc++), because most people don't care about
this and there is a cost associated to enabling the option (code
bloat because templates are not deduped across TUs).
I'm using '#pragma clang attribute push' to avoid marking each
declaration with an attribute, which quickly becomes difficult
to maintain.
llvm-svn: 368684
1b6d6e595b