diff --git a/library/sha256.c b/library/sha256.c
index 638188f..e3d3ea8 100644
--- a/library/sha256.c
+++ b/library/sha256.c
@@ -28,7 +28,11 @@
  *  http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
  */
 
+#if !defined(POLARSSL_CONFIG_FILE)
 #include "polarssl/config.h"
+#else
+#include POLARSSL_CONFIG_FILE
+#endif
 
 #if defined(POLARSSL_SHA256_C)