Incompatible versions of db.h and libdb
---------------------------------------

BerkeleyDB seems to have built correctly, but you get an error like this
when you run the test harness:

  $ make test
  PERL_DL_NONLAZY=1 /home/paul/perl/install/bin/perl5.00560 -Iblib/arch
  -Iblib/lib -I/home/paul/perl/install/5.005_60/lib/5.00560/i586-linux
  -I/home/paul/perl/install/5.005_60/lib/5.00560 -e 'use Test::Harness
  qw(&runtests $verbose); $verbose=0; runtests @ARGV;' t/*.t
  t/db-btree..........
  DB_File needs compatible versions of libdb & db.h
          you have db.h version 2.3.7 and libdb version 2.7.5
  BEGIN failed--compilation aborted at t/db-btree.t line 21.
  ...

Another variation on the theme of having two versions of Berkeley DB on
your system.

Solution: Setting the LIB & INCLUDE variables in config.in to point to the
          correct directories can sometimes be enough to fix this
          problem. If that doesn't work the easiest way to fix the
          problem is to either delete or temporarily rename the copies
          of db.h and libdb.a that you don't want BerkeleyDB to use.
          If you are running Linux, please read the Linux Notes section
          below.