Re: [Bug-tar] Please fix the build with gcc 8.1

[Paul Eggert]

Sergey Poznyakoff wrote:
> The ioctl code needs a good rewrite indeed. However, I'm more concerned
> about that:
>
> > /usr/include/bits/socket.h: In function ‘__cmsg_nxthdr’:
> > /usr/include/bits/socket.h:315:12: error: cast increases required alignment of 
> > target type [-Werror=cast-align]
> >     __cmsg = (struct cmsghdr *) ((unsigned char *) __cmsg
> The minimal reproducible file is a one-liner:
>
>    #include <netdb.h>
>
> Running
>   
>    gcc-8 -Wsystem-headers -Wcast-align=strict -Werror -O2 -c 1.c
>
> produces the error above.

Although that's annoying, it's a false alarm, since the code properly aligns the 
pointer before using it by using CMSG_ALIGN. The warning in rtapelib.c, though, 
is not so obviously a false alarm.