Fast forward to sync public repo.

Compile math.sinh(), math.cosh(), math.tanh() and math.random().
Compile various io.*() functions.
Drive the GC forward on string allocations in the parser.
Improve KNUM fuse vs. load heuristics.
Add abstract C call handling to IR.

src/lj_udata.c

@@ -16,6 +16,7 @@ GCudata *lj_udata_new(lua_State *L, MSize sz, GCtab *env)
   global_State *g = G(L);
   newwhite(g, ud);  /* Not finalized. */
   ud->gct = ~LJ_TUDATA;
+  ud->udtype = UDTYPE_USERDATA;
   ud->len = sz;
   /* NOBARRIER: The GCudata is new (marked white). */
   setgcrefnull(ud->metatable);