Merge branch 'upstream-zstd' into update-zstd

Utilities/cmzstd/LICENSE

Utilities/cmzstd/README.md

Utilities/cmzstd/lib/common/allocations.h

Utilities/cmzstd/lib/common/bits.h

Utilities/cmzstd/lib/common/bitstream.h

Utilities/cmzstd/lib/common/compiler.h

Utilities/cmzstd/lib/common/cpu.h

Utilities/cmzstd/lib/common/debug.c

Utilities/cmzstd/lib/common/debug.h

Utilities/cmzstd/lib/common/entropy_common.c

Utilities/cmzstd/lib/common/error_private.c

Utilities/cmzstd/lib/common/error_private.h

Utilities/cmzstd/lib/common/fse.h

Utilities/cmzstd/lib/common/fse_decompress.c

Utilities/cmzstd/lib/common/huf.h

Utilities/cmzstd/lib/common/mem.h

Utilities/cmzstd/lib/common/pool.c

Utilities/cmzstd/lib/common/pool.h

Utilities/cmzstd/lib/common/portability_macros.h

Utilities/cmzstd/lib/common/threading.c