diff --git a/library/x509.c b/library/x509.c
index e969b8d..55afbab 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -29,11 +29,7 @@
  *  http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf
  */
 
-#if !defined(MBEDTLS_CONFIG_FILE)
-#include "mbedtls/config.h"
-#else
-#include MBEDTLS_CONFIG_FILE
-#endif
+#include "common.h"
 
 #if defined(MBEDTLS_X509_USE_C)