Provide default values in pre.in for PROG_LIBPATH, PROG_RPATH,
SHLIB_DIRS, SHLIB_RDIRS, and STOBJLISTS so that they don't have to be
specified in the common case.  Rename KRB5_RUN_ENV and KRB5_RUN_VARS
to RUN_SETUP (already the most commonly used name) and RUN_VARS.  Make
sure to use DEFINES for local defines (not DEFS).  Remove some other
unnecessary makefile content.

entry must be initialized before all code which can jump to cleanup.

Mostly this gets rid of the trailing space on line 2 after
bb76891f5386526bdf91bc790c614fc9296cb5fa.

Outside of krb5_ldap_read_krbcontainer_params and
krb5_ldap_create_krbcontainer, no fields of
krb5_ldap_krbcontainer_params were used except for the DN.  There was
code to create a krbTicketPolicyReference attribute (which would fail
because the schema doesn't allow that attribute, and was never
exercised because kdb5_ldap_util would never set the parameter) and to
read fields like max ticket life from the referenced ticket policy,
but those fields were never used.

Eliminate the structure and just store the container DN in
krb5_ldap_context.  Continue creating the container object when
creating a realm (by calling krb5_ldap_create_krbcontainer
unconditionally; it now exits successfully if the container already
exists), but don't ever read it.

The old man pages are gone, so we can't install them anymore.
Also clean up install and install-unix targets that were installing
the old man pages by hand.

We generate man pages from RST sources now; they are checked into
the tree in src/man/.

The gen-manpages directory is no longer needed.