Log Message:
lz4: updated to 1.8.1

v1.8.1
perf : faster and stronger ultra modes (levels 10+)
perf : slightly faster compression and decompression speed
perf : fix bad degenerative case
fix : decompression failed when using a combination of extDict + low memory address
cli : support for dictionary compression (-D)
cli : fix : lz4 -d --rm preserves timestamp
cli : fix : do not modify /dev/null permission as root
api : _destSize() variant supported for all compression levels
build  : make and make test compatible with -jX
build  : can control LZ4LIB_VISIBILITY macro
install: fix man page directory