Improve the calc build and release process

We apologize for the calc v2.14.0.12 source tarball that was missing
critical files.  While the executable was well tested, our release
process was deficient.

We are improved our release process and added tests during the release
procedure to help verify that we are not regressing in to the "v2.14.0.12
source tarball" issue, among other things.

Depending on how things do, you might is several releases come out over
a short period of time.  The core of calc isn't changing, so the calc
executable will be the same as we focus on the Makefiles, our release
procedure, and related documentation / help files.

We made several changes to the Makefiles.  We also added a new
README.RELEASE document (see "help release") that is a work in
progress. Along the way we discovered a few things that needed to be
updated in documentation.

See the CHANGES file for details.

help/archive

@@ -1,21 +1,27 @@
 Where to get the latest versions of calc
 
-    Landon Noll maintains the official calc home page at:
+    Official calc source is maintained on GitHub:
+
+	https://github.com/lcn2/calc
+
+    Calc releases may be found as GitHub tagged releases:
+
+	https://github.com/lcn2/calc/releases?page=2
+
+     At the bottom of a given release is a "> Assets" that may
+     be opened to reveal down-loadable files such as source
+     tarballs, source zip files and RPMs.
+
+    Landon Noll also maintains a calc home page at:
 
 	    http://www.isthe.com/chongo/tech/comp/calc/
 
-    See:
-
-	    http://www.isthe.com/chongo/tech/comp/calc/calc-download.html
-
-    for information on how to obtain up a recent version of calc.
-
 Landon Curt Noll
 http://www.isthe.com/chongo/
 
 chongo <was here> /\../\
 
-## Copyright (C) 1999  Landon Curt Noll
+## Copyright (C) 1999,2021  Landon Curt Noll
 ##
 ## Calc is open software; you can redistribute it and/or modify it under
 ## the terms of the version 2.1 of the GNU Lesser General Public License