format string should be a string literal.

ok beck@ jsing@
Fix backtraces through _dl_bind_start by adding dwarf annotations for
the stack adjustments/handling in the asm.  Based on FreeBSD.

ok kettenis@ matthew@
Fix boot -d.  refreshcreds() should be called when trapping from userspace,
but I flipped the test on i386/amd64, thus breaking kernel traps before
enough proc0 bits were set up.  In theory, this could have resulted in
a NFS read for a page fault being done with a process's old credentials.

pointed out by Patrick Wildt of bitrig
instead of printf() use tbprintf() like elsewhere in systat.

ok deraadt@ mpi@
Set default of net.inet6.icmp6.nodeinfo to 0,
disables responses to RFC4620 IPv6 Node Information Queries.
ok florian henning bluhm
KNF