Bump to version 2.0.1

Hardened the code using static analysis and improved the build system
to work perfectly on OpenBSD and macOS.

Signed-off-by: Laslo Hunhold <dev@frign.de>

Makefile

diff --git a/Makefile b/Makefile
index 7e87720..53d42a6 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@
 
 VERSION_MAJOR = 2
 VERSION_MINOR = 0
-VERSION_PATCH = 0
+VERSION_PATCH = 1
 UNICODE_VERSION = 15.0.0
 MAN_DATE = 2022-10-06