Lock the database file with an explicit lock file.

ChangeLog

+1999-05-21  Per Cederqvist  <ceder@gratia>
+
+	Lock the database file with an explicit lock file.
+	* src/server/dbck.c (main): Lock and unlock the database.
+	* src/server/ramkomd.c (init_data_base): Log the name of the lock
+	file.
+	(initialize): Lock the database before opening it.
+	(main): Unlock the database.
+	* src/server/server-config.c (parameters): Added "Lock file".
+	(read_configuration): Handle param.lockfile_name.
+	* src/server/param.h (struct kom_par): Added lockfile_name.
+	* src/server/Makefile.am (lyskomd_SOURCES): Added lockdb.h and
+	lockdb.c.
+	(DBCK): Likewise.
+	* src/server/lockdb.c, src/server/lockdb.h: New files.
+ 	(lock_db): New function.
+	(unlock_db): New function.
+	* doc/lyskomd.texi (Parameters): Document "Lock file:".
+
 1999-05-20  Per Cederqvist  <ceder@signum.se>
 
 	Clean up the framework for hunting memory leaks.