Add a comment about needing to change a #include if using a version of

Berkeley DB 2.0 or newer; most Linux distros will include a more recent
version than 1.85.

Modules/bsddbmodule.c

@@ -51,6 +51,7 @@ PERFORMANCE OF THIS SOFTWARE.
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
+/* If using Berkeley DB 2.0 or newer, change this include to <db_185.h>: */
 #include <db.h>
 /* Please don't include internal header files of the Berkeley db package
    (it messes up the info required in the Setup file) */