[safestack] Use non-thread-local unsafe stack pointer for Contiki OS

Patch by Michael LeMay

Differential revision: http://reviews.llvm.org/D19852


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284254 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed