all: enhance CMake tests; assorted updates

doc/upx.1

@@ -936,8 +936,6 @@ Please report all bugs immediately to the authors.
 \& Laszlo Molnar <ezerotven+github@gmail.com>
 \&
 \& John F. Reiser <jreiser@BitWagon.com>
-\&
-\& Jens Medoch <jssg@users.sourceforge.net>
 .Ve
 .SH COPYRIGHT
 .IX Header "COPYRIGHT"
@@ -947,8 +945,6 @@ Copyright (C) 1996\-2024 Laszlo Molnar
 .PP
 Copyright (C) 2000\-2024 John F. Reiser
 .PP
-Copyright (C) 2002\-2024 Jens Medoch
-.PP
 \&\fBUPX\fR is distributed with full source code under the terms of the
 GNU General Public License v2+; either under the pure GPLv2+ (see
 the file COPYING), or (at your option) under the GPLv+2 with special