diff --git a/configure.ac b/configure.ac
index a2148ab..1b0bcf9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1052,6 +1052,18 @@ AC_ARG_ENABLE([bogofilter],
 	[AS_HELP_STRING([--enable-bogofilter],
 	[enable spam filtering using Bogofilter (default=yes)])],
 	[enable_bogofilter=$enableval], [enable_bogofilter=yes])
+case x"$enable_bogofilter" in
+xyes)
+	: ok
+	;;
+xno)
+	: ok
+	;;
+*)
+	BOGOFILTER=$enable_bogofilter
+	enable_bogofilter=yes
+	;;
+esac
 AC_MSG_CHECKING([if Bogofilter support is enabled])
 AC_MSG_RESULT([$enable_bogofilter])
 msg_bogofilter="$enable_bogofilter"
