diff --git a/pjlib/include/pj/config.h b/pjlib/include/pj/config.h
index 23becd7ca..4a063bed0 100644
--- a/pjlib/include/pj/config.h
+++ b/pjlib/include/pj/config.h
@@ -427,6 +427,17 @@
 #endif
 
 
+/**
+ * Specify if PJ_CHECK_STACK() macro is enabled to check the sanity of 
+ * the stack. The OS implementation may check that no stack overflow 
+ * occurs, and it also may collect statistic about stack usage. Note
+ * that this will increase the footprint of the libraries since it
+ * tracks the filename and line number of each functions.
+ */
+#ifndef PJ_OS_HAS_CHECK_STACK
+#	define PJ_OS_HAS_CHECK_STACK		0
+#endif
+
 /**
  * Do we have alternate pool implementation?
  *