Index: build/apr_hints.m4
--- build/apr_hints.m4.orig
+++ build/apr_hints.m4
@@ -135,6 +135,7 @@ dnl	       # Not a problem in 10.20.  Otherwise, who k
         esac
         ;;
     *-openbsd*)
+        APR_SETIFNULL(apr_lock_method, [USE_FLOCK_SERIALIZE])
 	APR_ADDTO(CPPFLAGS, [-D_POSIX_THREADS])
         # binding to an ephemeral port fails on OpenBSD so override
         # the test for O_NONBLOCK inheritance across accept().