I use version 3.0.18 (not 3.0.17, but the form here does not know about it).

configure does not find sendmail if the path to sendmail is the last one in your $PATH.

The patch for the problem is here. Sorry for broken format, but it seems I *have* to use
this web form. I'm sure you want to fix configure.in instead of configure, but you
get the idea. :) Maybe you should add /usr/lib to this path as sendmail is/was installed
there often.

--- configure.orig      Fri Oct 20 21:05:17 2000
+++ configure   Wed Jan 31 01:00:13 2001
@@ -1626,7 +1626,7 @@
   ;;
   *)
   IFS="${IFS=  }"; ac_save_ifs="$IFS"; IFS=":"
-  ac_dummy="$PATH /usr/bin /usr/sbin /usr/etc /etc /usr/ucblib"
+  ac_dummy="$PATH:/usr/bin:/usr/sbin:/usr/etc:/etc:/usr/ucblib"
   for ac_dir in $ac_dummy; do 
     test -z "$ac_dir" && ac_dir=.
     if test -f $ac_dir/$ac_word; then

The FreeBSD port fixes this problem (see patch-aq 2000/01/31)

Bye,
knarf