Building RocksDB on aarch64 and riscv64

Trying to build RocksDB on other little endian architectures I noticed this part in the CMake file..

#

# Also, disable on ARM64 when not Linux

# Requires submodule update to v6.16.3

# containing commit https://github.com/facebook/rocksdb/commit/ee4bd4780b321ddb5f92a0f4eb956f2a2ebd60dc

#

But looking at the commit history it looks like RocksDB was added and then has not been updated since.

To get RocksDB to build on riscv64 I needed..

• jemalloc_helper: Limit the mm_malloc.h hack to glibc on linux
  https://github.com/facebook/rocksdb/commit/bac399449d0bc8127a2bfb97e78c1ab6356b201c

Same also for aarch64. I also needed for aarch64..

• Check for sys/auxv.h
  https://github.com/facebook/rocksdb/commit/8bbd76edbfd0c187960aae31d107a9a0fa71472c
• Fix RocksDB SIGILL error on Raspberry PI 4
  https://github.com/facebook/rocksdb/commit/29f7bbef995bdf83098963799c66af742e95373f
• Fix compilation on Apple Silicon
  https://github.com/facebook/rocksdb/commit/ee4bd4780b321ddb5f92a0f4eb956f2a2ebd60dc
• Adding ARM AT_HWCAP support for FreeBSD
  https://github.com/facebook/rocksdb/commit/93c6c18cf9731f47b386dd445dc13363423c507e
• Add OpenBSD/arm64 support for detection of CRC32 and PMULL
  https://github.com/facebook/rocksdb/commit/4a6906e28ce058f6cea085b394a1adbd19aa468e