Description of Problem: ndbm.h resides in /usr/include/db1 and belongs to the db1-devel package, whereas libndbm.so is a symlink to libdb2.so and belongs to the db2-devel package. This induces unnecessary build dependencies (and potential problems) for perl and other sources that include ndbm.h and link against -lndbm.
The problem no more exist since db4.