When building the textproc/docproj port, the ports-mgmt/pkg port
needs /var/run/ld-elf*.so.hints, which is not automatically created.

Fix reldoc build by running the ldconfig(8) startup script in the
chroot directory before starting the port build phase.

MFC after:	3 days
Sponsored by:	The FreeBSD Foundation
Quiesce warning about unused argument in call to rl_message() by wrapping
this call with the same #if defined (PREFER_STDARG) directive as in display.c

Using -E to compile display.c/search.c shows that this is the code chosen by
the build when we create libreadline
Document RB_FOREACH_SAFE() and RB_FOREACH_REVERSE_SAFE().

Submitted by:	Mikhail <mp lenta.ru>