[compiler-rt] fix OpenBSD and Solaris build with sigaltstack interception

Summary:
`sigaltstack` interception is implemented D73816. This updated OpenBSD and Solaris bits to fix the build errors.

Reviewers: eugenis

Reviewed By: eugenis

Subscribers: fedor.sergeev, krytarowski, emaste, eugenis, dberris, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Patch by Igor Sugak.

Differential Revision: https://reviews.llvm.org/D73976