migration: Teach it about G_SOURCE_REMOVE

As this is defined on glib 2.32, add compatibility macros for older glibs.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
4 files changed