dbmmanage uses perl's NDBM module, which is actually Berkeley DB.  Aaaargh.
--- apache_1.3.23/src/modules/standard/mod_auth_dbm.c	Mon Feb 25 14:25:33 2002
+++ apache_1.3.23/src/modules/standard/mod_auth_dbm.c	Mon Feb 25 14:27:43 2002
@@ -81,7 +81,8 @@
 #define dbm_fetch sdbm_fetch
 #define dbm_close sdbm_close
 #else
-#include <ndbm.h>
+#define DB_DBM_HSEARCH 1
+#include <db.h>
 #endif
 
 /*
--- apache_1.3.27/src/modules/standard/mod_rewrite.h	2002-10-07 17:27:19.000000000 -0400
+++ apache_1.3.27/src/modules/standard/mod_rewrite.h	2002-10-07 17:27:13.000000000 -0400
@@ -130,7 +130,8 @@
      * so we also need to know the file extension
      */
 #ifndef NO_DBM_REWRITEMAP
-#include <ndbm.h>
+#define DB_DBM_HSEARCH 1
+#include <db.h>
 #if defined(DBM_SUFFIX)
 #define NDBM_FILE_SUFFIX DBM_SUFFIX
 #elif defined(__FreeBSD__) || (defined(DB_LOCK) && defined(DB_SHMEM))