When defining deprecated macros, annotate them with
`GLIB_DEPRECATED_MACRO_IN_*()` and `GLIB_DEPRECATED_MACRO_IN_*_FOR()` to
conditionally emit warnings if people use them, depending on their
declared minimum and maximum GLib version requirements (see
`GLIB_VERSION_MIN_REQUIRED` and `GLIB_VERSION_MAX_ALLOWED`).

The old way of doing this was for users to define `G_DISABLE_DEPRECATED`
if they didn’t want to use deprecated APIs, but it reported errors via
missing symbols, and wasn’t version-dependent. It’s being phased out.

Signed-off-by: Philip Withnall <withnall@endlessm.com>