philmd authored May 31, 2020 and Samuel Thibault committed Jun 01, 2020

A packed struct needs different gcc attributes for compilations
with MinGW compilers because glib-2.0 adds compiler flag
-mms-bitfields which modifies the packing algorithm.

Attribute gcc_struct reverses the negative effects of -mms-bitfields.

We already have the SLIRP_PACKED definition for that, use it.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>