G_SOURCE_FUNC has attribute GLIB_AVAILABLE_MACRO_IN_2_58, which means
that the compiler will emit a warning when GLIB_VERSION_MAX_ALLOWED <
GLIB_VERSION_2_58. We currently define GLIB_VERSION_MAX_ALLOWED as
GLIB_VERSION_2_40. Redefine the macro to fix the following build error
when using glib >= 2.63.5 (the version in which the attribute was
added):
CC shared/nm-glib-aux/libnm_glib_aux_la-nm-shared-utils.lo
shared/nm-glib-aux/nm-shared-utils.c: In function ‘nm_g_unix_fd_source_new’:
shared/nm-glib-aux/nm-shared-utils.c:3679:13: error: Not available before [-Werror]
3679 | g_source_set_callback (source, G_SOURCE_FUNC (source_func), user_data, destroy_notify);
Fixes: 9c5741ccd2 ('shared/nm-glib: add compat implementation for G_SOURCE_FUNC()')
7f801685b2