network: recvmmsg and sendmmsg standard compliance (BZ#16919)

network: recvmmsg and sendmmsg standard compliance (BZ#16919)

POSIX specifies that both msghdr::msg_iovlen and msghdr::msg_controllen
to be of size int and socklen_t respectively, however Linux implements
it as a size_t.  So for 64-bits architecture where sizeof of size_t is
larger than socklen_t, both sendmmsg and recvmmsg need to adjust the
mmsghdr::msg_hdr internal fields before issuing the syscall itself.

This patch fixes it by operating on the padding if it the case.
For recvmmsg, the most straightfoward case, only zero padding the fields
is suffice.  However, for sendmmsg, where adjusting the buffer is out
of the contract (since it may point to a read-only data), the function
is rewritten to use sendmsg instead (which from previous patch
allocates a temporary msghdr to operate on).

Also for 64-bit ports that requires it, a new recvmmsg and sendmmsg
compat version is created (which uses size_t for both cmsghdr::cmsg_len
and internal

Tested on x86_64, i686, aarch64, armhf, and powerpc64le.

	* sysdeps/unix/sysv/linux/Makefile
	[$(subdir) = socket] (sysdep_routines): Add oldrecvmmsg and
	oldsendmmsg.
	* sysdeps/unix/sysv/linux/aarch64/libc.abilist: Add recvmmsg and
	sendmmsg.
	* sysdeps/unix/sysv/linux/alpha/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/ia64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist: Likewise.
	* sysdeps/sysv/linux/powerpc/powerpc64/libc-le.abilist: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/oldrecvmmsg.c: New file.
	* sysdeps/unix/sysv/linux/oldsendmmsg.c: Likewise.
	* sysdeps/unix/sysv/linux/recvmmsg.c (__recvmmsg): Adjust msghdr
	iovlen and controllen fields to adjust to POSIX specification.
	* sysdeps/unix/sysv/linux/sendmmsg.c (__sendmmsg): Likewise.