Fails to build on 32-bit architectures (e.g., armv7, i386, powerpc)

[jbeich]

Regressed by #164. From error log:

$ export CFLAGS=-m32
$ gmake || make
[...]
lib/col/src/itable.c:317:60: error: format specifies type 'unsigned long' but the argument has type 'uint64_t' (aka 'unsigned long long') [-Werror,-Wformat]
  317 |                 bufp += snprintf(bufp, len - (bufp - buf), "%lu = %s\n", *k, *v ? (char*)*v : "(null)");
      |                                                             ~~~          ^~
      |                                                             %llu

[alex-courtis]

Thanks for letting me know, I'll get back to you on the weekend