Updating the LF MPMC queue and replacing DirQueue with it

Making the MPMC queue support when producers are consumers at the same
time by adding a variable work, mpmc_push_work() that increments work
and mpmc_task_done() that decrements work, and if work = 0 calls
mpmc_producers_finished() that pushes poinsons to wake up sleeping
threads and make them return NULL

Replacing DirQueue, a queue growable with realloc with the MPMC queue

base.h

@@ -29,13 +29,6 @@
 #include <unistd.h>
 #endif
 
-#define XXH_VECTOR                                                             \
-  XXH_AVX2 // not recommanded to compile with gcc see xxhash.h line 4082
-           // Must compile with /arch:AVX2 in clang-cl or -mavx2 in clang/gcc
-#define XXH_INLINE_ALL
-#include "xxhash.c"
-#include "xxhash.h"
-
 /* ------------------------------------------------------------
    Base types
    ------------------------------------------------------------ */