[Exim] Error Building exim-3.22

Anybody got any ideas why exim 3.22 won't make it past this point?

---
gcc -O  -o exim_dbmbuild  exim_dbmbuild.c \
  -lnsl -lcrypt  -ldb
In file included from exim.h:332,
                 from exim_dbmbuild.c:30:
dbfn.h:107: db.h: No such file or directory
make[1]: *** [exim_dbmbuild] Error 1
make[1]: Leaving directory `/usr/src/exim-3.22/build-Linux-i386'
make: *** [go] Error 2
---

TIA, Cal