Summary:
ASan/MSan/LSan allocators set errno on allocation failures according to
malloc/calloc/etc. expected behavior.
MSan allocator was refactored a bit to make its structure more similar
with other allocators.
Also switch Scudo allocator to the internal errno definitions.
TSan allocator changes will follow.
Reviewers: eugenis
Subscribers: llvm-commits, kubamracek
Differential Revision: https://reviews.llvm.org/D35275
llvm-svn: 308344