[Exim] Infamous DB3 problem

I just ran into the DB3 problem on a not-quite-RH6.2 S/390 system
(glibc 2.1.3). I had installed DB3 in preparation for moving to RPM 4.
On this system, the problem looks a little different:

gcc -O -o exim_dbmbuild exim_dbmbuild.c \
-lnsl -lcrypt -ldb
/tmp/john-tmp.13990/files/ccfXtTJh.o: In function `main':
/tmp/john-tmp.13990/files/ccfXtTJh.o(.text+0x25c): undefined reference
to `db_open'
collect2: ld returned 1 exit status
make[1]: *** [exim_dbmbuild] Error 1
make[1]: Leaving directory
`/home/john/tgz/tmp/exim-3.22/build-Linux-s390'
make: *** [go] Error 2

Apparently the default search paths find the DB3 library but the DB2
include file. Setting INCLUDE fixed the problem.
John