Upgrading a RH7 box with the db3 update in
http://www.redhat.com/support/errata/RHEA-2001-015.html broke a custom
perl application here. Installed packages were:

db1-1.85-4
db1-devel-1.85-4
db2-2.4.14-4
db3-3.1.17-5
db3-devel-3.1.17-5
db3-utils-3.1.17-5

and the perl error was:

DB_File needs compatible versions of libdb & db.h
        you have db.h version 3.1.14 and libdb version 3.1.17

But db3-devel-3.1.17-5 should provide the correct db.h
(/usr/include/db3/db.h and the symlink /usr/include/db.h)!
Anyway, reverting to the 3.1.14-6 versions of the db3 packages (from
stock RH7) solved the problems. But it seems there is something strange
with the db3-*3.1.17-5* packages from the errata.