[Box Backup] Berkeley DB: no

[Felix E. Klee]

I'm trying to build boxbackup 0.10, but I cannot get "configure" to find
the Berkeley database:

  $ ls /opt/BerkeleyDB.4.4/
  bin  docs  include  lib
  $ ls /opt/BerkeleyDB.4.4/include/
  db.h  db_cxx.h
  $ ./configure --with-bdb-dir=/opt/BerkeleyDB.4.4
  [...]
  checking db.h presence in /opt/BerkeleyDB.4.4/include... yes
  checking for db.h... no
  configure: no Berkeley DB version  or higher found
  [...]
  Large files:         no
  Berkeley DB:         no
  Readline:            yes
  Extended attributes: yes

What may be the reason for the problem, and how do I solve it?

-- 
Felix E. Klee