int error = lua_pcall(lua_State *L, int nargs, int nrvals, int errfunc);
lua_pcall() function except that it
returns a Hollywood error code if something goes wrong. On success, 0 is
returned which is the same behaviour as in Lua's lua_pcall().
Furthermore, the errfunc parameter is not supported and must be 0.
The Hollywood version of lua_pcall() also won't push the error message
on the stack.
Finally, you should always set HWMCP_SETCALLBACKMODE to True before
calling lua_pcall() and reset it to False when lua_pcall() returns.
See hw_MasterControl for details.
Note that up to and including Hollywood 6.1 lua_pcall() didn't keep the
stack balanced in case an error was returned. This has been fixed for
Hollywood 6.2.
lua_State