Log Message:
zstd: updated to 1.3.3

1.3.3:
perf: improved zstd_opt strategy (levels 16-19)
fix : bug 944 : multithreading with shared ditionary and large data
cli : fix : content size written in header by default
cli : fix : improved LZ4 format support
cli : new : hidden command -b -S, to benchmark multiple files and generate one \ 
result per file
api : change : when setting pledgedSrcSize, use ZSTD_CONTENTSIZE_UNKNOWN macro \ 
value to mean "unknown"
api : fix : support large skippable frames
api : fix : re-using context could result in suboptimal block size in some \ 
corner case scenarios
api : fix : streaming interface was adding a useless 3-bytes null block to small \ 
frames
build: fix : compilation under rhel6 and centos6
build: added check target
build: improved meson support