diff --git a/library/rsa.c b/library/rsa.c
index 1786149..9cfbe2a 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -29,7 +29,11 @@
  *  http://www.cacr.math.uwaterloo.ca/hac/about/chap8.pdf
  */
 
+#if !defined(POLARSSL_CONFIG_FILE)
 #include "polarssl/config.h"
+#else
+#include POLARSSL_CONFIG_FILE
+#endif
 
 #if defined(POLARSSL_RSA_C)