diff --git a/m4/acx_openssl.m4 b/m4/acx_openssl.m4
index 7f5ad0f8..135131fb 100644
--- a/m4/acx_openssl.m4
+++ b/m4/acx_openssl.m4
@@ -95,6 +95,12 @@ AC_DEFUN([ACX_SSL_CHECKS], [
         fi
         AC_SUBST(HAVE_SSL)
         AC_SUBST(RUNTIME_PATH)
+	# openssl engine functionality needs dlopen().
+	BAKLIBS="$LIBS"
+	AC_SEARCH_LIBS([dlopen], [dl])
+	if test "$LIBS" != "$BAKLIBS"; then
+		LIBSSL_LIBS="$LIBSSL_LIBS -ldl"
+	fi
     fi
 AC_CHECK_HEADERS([openssl/ssl.h],,, [AC_INCLUDES_DEFAULT])
 AC_CHECK_HEADERS([openssl/err.h],,, [AC_INCLUDES_DEFAULT])