[Bug go/69966] libgo: Port syscall.SetsockoptUcred from golang

[ian at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69966

--- Comment #1 from ian at gcc dot gnu.org <ian at gcc dot gnu.org> ---
Author: ian
Date: Fri Feb 26 17:36:00 2016
New Revision: 233747

URL: https://gcc.gnu.org/viewcvs?rev=233747&root=gcc&view=rev
Log:
        PR go/69966
    syscall: Add new Getsockopt functions.

    Add GetsockoptICMPv6Filter, GetsockoptIPv6MTUInfo, GetsockoptUcred as
    appropriate.  These functions exist in the master library.

    For GCC PR 69966.

    Reviewed-on: https://go-review.googlesource.com/19960

Modified:
    trunk/gcc/go/gofrontend/MERGE
    trunk/libgo/go/syscall/socket.go
    trunk/libgo/go/syscall/socket_bsd.go
    trunk/libgo/go/syscall/socket_linux.go
    trunk/libgo/mksysinfo.sh