Fix for missing len var when XTS config'd and CTR not
The AES XTS self-test was using a variable len, which was declared only when CTR
was enabled. Changed the declaration of len to be conditional on CTR and XTS.
diff --git a/library/aes.c b/library/aes.c
index 5cd96ec..23efdb8 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -1713,8 +1713,10 @@
#if defined(MBEDTLS_CIPHER_MODE_CTR) || defined(MBEDTLS_CIPHER_MODE_CFB)
size_t offset;
#endif
-#if defined(MBEDTLS_CIPHER_MODE_CTR)
+#if defined(MBEDTLS_CIPHER_MODE_CTR) || defined(MBEDTLS_CIPHER_MODE_XTS)
int len;
+#endif
+#if defined(MBEDTLS_CIPHER_MODE_CTR)
unsigned char nonce_counter[16];
unsigned char stream_block[16];
#endif
