fix #481: ensure liblz4.a dependency for `make all`
fix #481: ensure liblz4.a dependency for `make all`

`make all` will trigger several sub-directory makefiles.
several of them need `liblz4.a`.
When built with `-j#`, there are several concurrent liblz4.a built

Make liblz4.a a dependency, which is built once,
before moving to sub-directory Makefiles

unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso