diff --git a/library/bignum.c b/library/bignum.c
index d9ab6f6..2ab71ca 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -35,11 +35,7 @@
  *
  */
 
-#if !defined(MBEDTLS_CONFIG_FILE)
-#include "mbedtls/config.h"
-#else
-#include MBEDTLS_CONFIG_FILE
-#endif
+#include "common.h"
 
 #if defined(MBEDTLS_BIGNUM_C)