MFC r245752,246913,247162

Replace all known uses of ln in the build process with appropriate
install -l invocations via new INSTALL_LINK and INSTALL_SYMLINK
variables.

Sponsored by:	DARPA, AFRL
MFC r245753:

Install the template info directory with mode 644 instead of 444 to
allow it to be updated by its owner without resorting to privilege.

This is required by upcoming changes to allow installworld to work as
a non-root user.

Sponsored by:   DARPA, AFRL
MFC r245853:

manctl is conditionally added to SUBDIRS later on.  Don't unconditionally
include in the main list.
MFC r245882,245898

Reorder so that NO_MAN is declared before bsd.own.mk is included and thus
has an effect (not installed a g++.1 manpage over the g++.1(.gz) link
created in ../cc).

bsd.own.mk needs to be included before Makefil.inc so MK_ARM_EABI is defined
MFC: 242030

Show how many times we are blocked waiting for mbufs.