It appears that /usr/include/db.h /usr/lib/libdb.so and /usr/lib/libdb.a are missing in glibc-devel-2.1.92-14. In RH 6.1 these files were provided by glibc-devel-2.1.2-11. This caused a build of the DB_File Perl module to die. Putting symlinks to /usr/include/db1/db.h /usr/lib/libdb1.so and /usr/lib/libdb1.a seems to correct the problem...
glibc no longer provides Berkeley DB libraries. Install some of db1, db1-devel, db2, db2-devel, db3, db3-devel packages you need.