Run ldconfig(8) rc script before building ports so

ld-elf.so.hints exists for pkg(8).

This is a direct commit to stable/10 as generate-release.sh
does not exist in head/.

PR:		186554
Sponsored by:	The FreeBSD Foundation

release/generate-release.sh

@@ -109,6 +109,7 @@ if [ -d ${CHROOTDIR}/usr/doc ]; then
 	cp /etc/resolv.conf ${CHROOTDIR}/etc/resolv.conf
 
 	# Install docproj to build release documentation
+	${CHROOT_CMD} /etc/rc.d/ldconfig forcerestart
 	${CHROOT_CMD} /bin/sh -c \
 		'make -C /usr/ports/textproc/docproj \
 			BATCH=yes \