Auto merge of #52431 - semarie:compiler-builtins, r=alexcrichton

update compiler-builtins for openbsd

import rust-lang-nursery/compiler-builtins/pull/249 in rust main line.

it solves an issue on OpenBSD with building of `librsvg`.
This commit is contained in:
bors
2018-07-18 22:15:46 +00:00