linux-user: correctly align types in thunking code

linux-user: correctly align types in thunking code

This is a follow up
of patch:

        commit c2e3dee6e03527baf8698698cce76b1a3174969a
        Author: Laurent Vivier <laurent@vivier.eu>
        Date:   Sun Feb 13 23:37:34 2011 +0100

            linux-user: Define target alignment size

In my case m68k aligns "int" on 2 not 4. You can check this with the
following program:

int main(void)
{
        struct rtentry rt;
        printf("rt_pad1 %ld %zd\n", offsetof(struct rtentry, rt_pad1),
                sizeof(rt.rt_pad1));
        printf("rt_dst %ld %zd\n", offsetof(struct rtentry, rt_dst),
                sizeof(rt.rt_dst));
        printf("rt_gateway %ld %zd\n", offsetof(struct rtentry, rt_gateway),
                sizeof(rt.rt_gateway));
        printf("rt_genmask %ld %zd\n", offsetof(struct rtentry, rt_genmask),
                sizeof(rt.rt_genmask));
        printf("rt_flags %ld %zd\n", offsetof(struct rtentry, rt_flags),
                sizeof(rt.rt_flags));
        printf("rt_pad2 %ld %zd\n", offsetof(struct rtentry, rt_pad2),
                sizeof(rt.rt_pad2));
        printf("rt_pad3 %ld %zd\n", offsetof(struct rtentry, rt_pad3),
                sizeof(rt.rt_pad3));
        printf("rt_pad4 %ld %zd\n", offsetof(struct rtentry, rt_pad4),
                sizeof(rt.rt_pad4));
        printf("rt_metric %ld %zd\n", offsetof(struct rtentry, rt_metric),
                sizeof(rt.rt_metric));
        printf("rt_dev %ld %zd\n", offsetof(struct rtentry, rt_dev),
                sizeof(rt.rt_dev));
        printf("rt_mtu %ld %zd\n", offsetof(struct rtentry, rt_mtu),
                sizeof(rt.rt_mtu));
        printf("rt_window %ld %zd\n", offsetof(struct rtentry, rt_window),
                sizeof(rt.rt_window));
        printf("rt_irtt %ld %zd\n", offsetof(struct rtentry, rt_irtt),
                sizeof(rt.rt_irtt));
}

And result is :

i386

rt_pad1 0 4
rt_dst 4 16
rt_gateway 20 16
rt_genmask 36 16
rt_flags 52 2
rt_pad2 54 2
rt_pad3 56 4
rt_pad4 62 2
rt_metric 64 2
rt_dev 68 4
rt_mtu 72 4
rt_window 76 4
rt_irtt 80 2

m68k

rt_pad1 0 4
rt_dst 4 16
rt_gateway 20 16
rt_genmask 36 16
rt_flags 52 2
rt_pad2 54 2
rt_pad3 56 4
rt_pad4 62 2
rt_metric 64 2
rt_dev 66 4
rt_mtu 70 4
rt_window 74 4
rt_irtt 78 2

This affects the "route" command :

WITHOUT this patch:

$ sudo route add -net default gw 10.0.3.1 window 1024 irtt 2 eth0
$ netstat -nr
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         10.0.3.1        0.0.0.0         UG        0 67108866  32768 eth0
10.0.3.0        0.0.0.0         255.255.255.0   U         0 0          0 eth0

WITH this patch:

$ sudo route add -net default gw 10.0.3.1 window 1024 irtt 2 eth0
$ netstat -nr
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         10.0.3.1        0.0.0.0         UG        0 1024       2 eth0
10.0.3.0        0.0.0.0         255.255.255.0   U         0 0          0 eth0

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20180510205949.26455-1-laurent@vivier.eu>