Port of bitcoin/#10958 - leveldb patches
Summary:
Includes:
bitcoin-core/leveldb#2: Prefer std::atomic over MemoryBarrier (Pieter Wuille) bitcoin-core/leveldb#5: Move helper functions out of sse4.2 object (Cory Fields) bitcoin-core/leveldb#6: Fixes typo (Dimitris Tsapakidis) bitcoin-core/leveldb#10: Clean up compile-time warnings (gcc 7.1) (Matt Corallo) bitcoin-core/leveldb#11: fixup define checks. Cleans up some oopses from #5 (Cory Fields)
Removes many warnings on MacOSX of the form:
In file included from leveldb/util/cache.cc:10: In file included from ./leveldb/port/port.h:14: In file included from ./leveldb/port/port_posix.h:47: ./leveldb/port/atomic_pointer.h:55:3: warning: 'OSMemoryBarrier' is deprecated: first deprecated in macOS 10.12 - Use std::atomic_thread_fence() from <atomic> instead [-Wdeprecated-declarations] OSMemoryBarrier(); ^
The bitcoin core patches have been included in BU already by sickpig.
Test Plan: make check. Installed and running fine.
Reviewers: #bitcoin_abc, deadalnix
Reviewed By: #bitcoin_abc, deadalnix
Differential Revision: https://reviews.bitcoinabc.org/D584