build: Turn off tautological-constant-out-of-range-compare warning

build: Turn off tautological-constant-out-of-range-compare warning

This issues a warning when an enum value is compared to a value that is
out of range for the enum.

We do this a lot, either when using -1 for undefined values or when
comparing array sizes to enum values like so:

  enum {
    ONE,
    TWO,
    THREE
  } some_enum_value;
  const char *names= { "one", "two", "three" };

  g_assert (some_enum_value < G_N_ELEMENTS (names));