maint: bump release version to 4.

* configure.ac (AC_INIT): Bump release version to 4.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
configury: make rules cleanup.

* lib/zmacs/zmacs.mk (lib/zmacs/zmacs.1.in): Use the sed and
$(MKDIR_P) idiom to make a lib/zmacs directory if necessary.
(clean-local): Append `|| :' to avoid an ignored error output
from the rule.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
maint: commit COPYING license.

* COPYING: Check in to avoid a warning from Automake.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>