doc: Mention new glibc headers and functions. * doc/glibc-headers/uchar.texi: New file. * doc/glibc-functions/aligned_alloc.texi: New file. * doc/glibc-functions/c16rtomb.texi: New file. * doc/glibc-functions/c32rtomb.texi: New file. * doc/glibc-functions/clock_adjtime.texi: New file. * doc/glibc-functions/fanotify_init.texi: New file. * doc/glibc-functions/fanotify_mark.texi: New file. * doc/glibc-functions/inet6_opt_append.texi: New file. * doc/glibc-functions/inet6_opt_find.texi: New file. * doc/glibc-functions/inet6_opt_finish.texi: New file. * doc/glibc-functions/inet6_opt_get_val.texi: New file. * doc/glibc-functions/inet6_opt_init.texi: New file. * doc/glibc-functions/inet6_opt_next.texi: New file. * doc/glibc-functions/inet6_opt_set_val.texi: New file. * doc/glibc-functions/inet6_rth_add.texi: New file. * doc/glibc-functions/inet6_rth_getaddr.texi: New file. * doc/glibc-functions/inet6_rth_init.texi: New file. * doc/glibc-functions/inet6_rth_reverse.texi: New file. * doc/glibc-functions/inet6_rth_segments.texi: New file. * doc/glibc-functions/inet6_rth_space.texi: New file. * doc/glibc-functions/login.texi: New file. * doc/glibc-functions/mbrtoc16.texi: New file. * doc/glibc-functions/mbrtoc32.texi: New file. * doc/glibc-functions/name_to_handle_at.texi: New file. * doc/glibc-functions/ntp_gettimex.texi: New file. * doc/glibc-functions/open_by_handle_at.texi: New file. * doc/glibc-functions/prlimit.texi: New file. * doc/glibc-functions/process_vm_readv.texi: New file. * doc/glibc-functions/process_vm_writev.texi: New file. * doc/glibc-functions/recvmmsg.texi: New file. * doc/glibc-functions/scandirat.texi: New file. * doc/glibc-functions/sendmmsg.texi: New file. * doc/glibc-functions/setns.texi: New file. * doc/glibc-functions/timespec_get.texi: New file. * doc/gnulib.texi: Include them. (Glibc sys/fanotify.h, Glibc sys/resource.h, Glibc uchar.h): New sections. Reported by Eric Blake.

new file mode 100644
--- /dev/null
+++ b/doc/glibc-functions/setns.texi
@@ -0,0 +1,16 @@
+@node setns
+@subsection @code{setns}
+@findex setns
+
+Gnulib module: ---
+
+Portability problems fixed by Gnulib:
+@itemize
+@end itemize
+
+Portability problems not fixed by Gnulib:
+@itemize
+@item
+This function is missing on all non-glibc platforms:
+glibc 2.13, MacOS X 10.5, FreeBSD 6.4, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 7.1, HP-UX 11.31, IRIX 6.5, OSF/1 5.1, Solaris 11 2011-11, Cygwin, mingw, MSVC 9, Interix 3.5, BeOS.
+@end itemize