- Let libcdk6_3_4 conflict with older libcdk6_2_4

- Update to version 5.0.20230201
+ improve compiler-warnings in configure-checks.
+ change library dependencies in rpm spec-file.
+ update license in test-packages.
+ relicense as MIT-X11
+ reduce shellcheck warnings in support-scripts
+ updated configure script to work around regression in GNU grep 3.8
+ updated configure macros from xterm and ncurses development
+ update config.guess, config.sub
+ fix cppcheck style-warnings.
+ improve makefile header-dependencies by accounting for all generated
headers (report/patch by Sergei Trofimovich).
+ updated configure macros from xterm and ncurses development:
CF_ADD_INCDIR CF_APPEND_CFLAGS CF_DISABLE_ECHO CF_MAKEFLAGS
CF_NCURSES_CONFIG CF_NCURSES_LIBS CF_PKG_CONFIG CF_REMOVE_CFLAGS
CF_SHARED_OPTS CF_TRY_XOPEN_SOURCE CF_XOPEN_SOURCE
+ build-fix for HP-UX curses, which provides only part of the ACS_xxx
definitions compatible with chtype's.
+ correct calls on SetViewSize in scroll.c, overlooked in 2005/04/24
(report by Brad Hines).
+ updated configure macros from xterm and ncurses development:
CF_C11_NORETURN CF_CHECK_LIBTOOL_VERSION CF_CONST_X_STRING
CF_DISABLE_LEAKS CF_FUNC_LSTAT CF_GETOPT_HEADER CF_NCURSES_CONFIG
CF_NO_LEAKS_OPTION CF_SHARED_OPTS CF_UTF8_LIB CF_XOPEN_CURSES
CF_XOPEN_SOURCE
+ update config.guess, config.sub
+ updated configure script, for _Noreturn and exit_curses checks.
+ spelling fixes, per codespell.