./configure does not find libmilter on systems, where libmilter is in lib64. This fixes it:
diff --git a/configure.ac b/configure.ac
index b257f23..d47e723 100644
--- a/configure.ac
+++ b/configure.ac
@@ -966,7 +966,7 @@ then
LDFLAGS="$outer_LDFLAGS $PTHREAD_CFLAGS $saved_LDFLAGS"
breakloop="no"
Applied for next release. Thanks!
v2.9.1 released.