diff --git a/includes-ros1/ecl-core/ecl-core_common.inc b/includes-ros1/ecl-core/ecl-core_common.inc
index f1f274a..1e005d8 100644
--- a/includes-ros1/ecl-core/ecl-core_common.inc
+++ b/includes-ros1/ecl-core/ecl-core_common.inc
@@ -1,3 +1,6 @@
 # Copyright (c) 2019 LG Electronics, Inc.
 
 inherit ros-insane
+
+# NB. Not needed for thud.
+EXTRA_OECMAKE += "-DTHREADS_PTHREAD_ARG=-pthread"