liblz4: convert to meson

Faster compilation

Before:

Executed in   13.68 secs   fish           external
   usr time   12.51 secs    0.00 micros   12.51 secs
   sys time    1.78 secs  345.00 micros    1.78 secs

After:

Executed in    9.60 secs   fish           external
   usr time   10.66 secs  281.00 micros   10.66 secs
   sys time    1.39 secs   36.00 micros    1.39 secs

Signed-off-by: Rosen Penev <rosenp@gmail.com>