Adapt sources to configurable config.h name
diff --git a/include/polarssl/cipher_wrap.h b/include/polarssl/cipher_wrap.h
index 63bd093..49d2661 100644
--- a/include/polarssl/cipher_wrap.h
+++ b/include/polarssl/cipher_wrap.h
@@ -29,7 +29,11 @@
 #ifndef POLARSSL_CIPHER_WRAP_H
 #define POLARSSL_CIPHER_WRAP_H
 
+#if !defined(POLARSSL_CONFIG_FILE)
 #include "config.h"
+#else
+#include POLARSSL_CONFIG_FILE
+#endif
 #include "cipher.h"
 
 #ifdef __cplusplus