Setting a pointer value to "0xdeadbeef" draws a warning from some
compilers, and for good reason.  Be less cute and just set it to NULL.

In passing make some other cosmetic adjustments nearby.

Discussion: https://postgr.es/m/CAJrrPGdW3EkU-CRobvVKYf3fJuBdgWyuGeAbNzAQ4yBh+bfb_Q@mail.gmail.com