Merge branch 'dev' into adapt

diff --cc doc/zstd_manual.html
Simple merge

diff --cc lib/compress/zstd_compress.c
Simple merge

diff --cc lib/compress/zstdmt_compress.c
Simple merge

diff --cc lib/zstd.h
Simple merge

diff --cc programs/fileio.c
Simple merge

diff --cc programs/fileio.h
Simple merge

diff --cc programs/zstd.1.md
Simple merge

diff --cc programs/zstdcli.c
Simple merge