Add configuration file in md.h
include `*config.h*` in md.h as MACROS in the header file get ignored.
Fix for #1001.
diff --git a/include/mbedtls/md.h b/include/mbedtls/md.h
index 9b996a9..89be847 100644
--- a/include/mbedtls/md.h
+++ b/include/mbedtls/md.h
@@ -27,6 +27,12 @@
#include <stddef.h>
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
#define MBEDTLS_ERR_MD_FEATURE_UNAVAILABLE -0x5080 /**< The selected feature is not available. */
#define MBEDTLS_ERR_MD_BAD_INPUT_DATA -0x5100 /**< Bad input parameters to function. */
#define MBEDTLS_ERR_MD_ALLOC_FAILED -0x5180 /**< Failed to allocate memory. */