linux-user: convert ioctl(SIOCGIFCONF, ...) result.

linux-user: convert ioctl(SIOCGIFCONF, ...) result.

The result needs to be converted as it is stored in an array of struct
ifreq and sizeof(struct ifreq) differs according to target and host
alignment rules.

This patch allows to execute correctly the following program on arm
and m68k:

 #include <stdio.h>
 #include <sys/ioctl.h>
 #include <net/if.h>
 #include <alloca.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>

int main(void)
{
    int s, ret;
    struct ifconf ifc;
    int i;

    memset( &ifc, 0, sizeof( struct ifconf ) );
    ifc.ifc_len = 8 * sizeof(struct ifreq);
    ifc.ifc_buf = alloca(ifc.ifc_len);

    s = socket( AF_INET, SOCK_DGRAM, 0 );
    if (s < 0) {
        perror("Cannot open socket");
        return 1;
    }
    ret = ioctl( s, SIOCGIFCONF, &ifc );
    if (s < 0) {
        perror("ioctl() failed");
        return 1;
    }

    for (i = 0; i < ifc.ifc_len / sizeof(struct ifreq) ; i ++) {
        struct sockaddr_in *s;
        s = (struct sockaddr_in*)&ifc.ifc_req[i].ifr_addr;
        printf("%s\n", ifc.ifc_req[i].ifr_name);
        printf("%s\n", inet_ntoa(s->sin_addr));
    }
}

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Riku Voipio <riku.voipio@iki.fi>