diff --git a/include/polarssl/threading.h b/include/polarssl/threading.h
index 8707152..1fc9f98 100644
--- a/include/polarssl/threading.h
+++ b/include/polarssl/threading.h
@@ -27,7 +27,11 @@
 #ifndef POLARSSL_THREADING_H
 #define POLARSSL_THREADING_H
 
+#if !defined(POLARSSL_CONFIG_FILE)
 #include "config.h"
+#else
+#include POLARSSL_CONFIG_FILE
+#endif
 
 #include <stdlib.h>