--- Makefile	(Asterisk 13.20)
+++ Makefile	(working copy)
@@ -231,3 +231,3 @@
 ifeq ($(OSARCH),NetBSD)
-  _ASTCFLAGS+=-pthread -I/usr/pkg/include
+  _ASTCFLAGS+=-pthread -D__LIBPTHREAD_SOURCE__ -I/usr/pkg/include
 endif