resolve/remove USAGE_LICENSE macros; remove repetitive (c) strings

This takes another small step towards disentangling the build
system from the old AT&T environment. The USAGE_LICENSE macros with
author and copyright information, which was formerly generated
dynamically for each file from a database, are eliminated and the
copyright/author information is instead inserted into the AST
getopt usage strings directly.

Repetitive license/copyright information is also removed from the
getopt strings in the builtin commands (src/lib/libcmd/*.c and
src/cmd/ksh93/data/builtins.c). There's no need to include 55
identical license/copyright strings in the ksh binary; one (in the
main ksh getopt string, shown by ksh --man) ought to be enough!
This makes the ksh binary about 10k smaller.

It does mean that something like 'enum --author', 'typeset
--license' or 'shift --copyright' will now not show those notices
for those builtins, but I doubt anyone will care.

src/lib/libcmd/sync.c

@@ -27,7 +27,7 @@
 
 static const char usage[] =
 "[-?\n@(#)$Id: sync (AT&T Research) 2006-10-04 $\n]"
-USAGE_LICENSE
+"[--catalog?" ERROR_CATALOG "]"
 "[+NAME?sync - schedule file system updates]"
 "[+DESCRIPTION?\bsync\b calls \bsync\b(2), which causes all information "
     "in memory that updates file systems to be scheduled for writing out to "