add dist to clean

- fix regex match padding
- fix key copying
- add more unit tests

Makefile

@@ -10,7 +10,7 @@ install: all
 	sudo ninja -C install
 
 clean:
-	rm -rf build dbtool*core* dbtool.1 test.db
+	rm -rf build dbtool*core* dbtool.1 test.db clean
 
 test:
 	@.woodpecker/test.sh

README.md

@@ -17,7 +17,7 @@ data and speed.
 You need either the GNU gdbm library or the Berkeley database
 system. You can find gdbm at:
   http://www.gnu.org/software/gdbm/gdbm.html
-And the berkeley library at: http://www.sleepycat.com.
+And the berkeley library at: https://libdb.org/.
 
 You will also need `meson` and `ninja`: https://mesonbuild.com/.