asterisk.c: Make displayed copyright always consistent

Change-Id: I4f5499486e8ec90d7c7ffeebc659ceda1db6d5b5

main/asterisk.c

@@ -294,9 +294,12 @@ int daemon(int, int);  /* defined in libresolv of all places */
 #define AST_MAX_CONNECTS 128
 #define NUM_MSGS 64
 
+/*! Displayed copyright tag */
+#define COPYRIGHT_TAG "Copyright (C) 1999 - 2018, Digium, Inc. and others."
+
 /*! \brief Welcome message when starting a CLI interface */
 #define WELCOME_MESSAGE \
-    ast_verbose("Asterisk %s, Copyright (C) 1999 - 2018, Digium, Inc. and others.\n" \
+    ast_verbose("Asterisk %s, " COPYRIGHT_TAG "\n" \
                 "Created by Mark Spencer <markster@digium.com>\n" \
                 "Asterisk comes with ABSOLUTELY NO WARRANTY; type 'core show warranty' for details.\n" \
                 "This is free software, with components licensed under the GNU General Public\n" \
@@ -3285,7 +3288,7 @@ static int show_version(void)
 
 static int show_cli_help(void)
 {
-	printf("Asterisk %s, Copyright (C) 1999 - 2018, Digium, Inc. and others.\n", ast_get_version());
+	printf("Asterisk %s, " COPYRIGHT_TAG "\n", ast_get_version());
 	printf("Usage: asterisk [OPTIONS]\n");
 	printf("Valid Options:\n");
 	printf("   -V              Display version number and exit\n");