Add a common.m4 file to be included directly in other project.
This include will include all needed checks to use spice-common.
Just include directly this file in your configure.ac.
This will define SPICE_COMMON_CFLAGS and SPICE_COMMON_DIR (for
linking .la files) which are needed to use spice-common.
Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
Acked-by: Kevin Pouget <kpouget@redhat.com>