Allow configuring MBEDTLS_TLS_EXT_CID at compile time

The numerical identifier of the CID extension hasn't been settled yet
and different implementations use values from different drafts. Allow
configuring the value at compile time.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/programs/test/query_config.c b/programs/test/query_config.c
index 9760f62..8382388 100644
--- a/programs/test/query_config.c
+++ b/programs/test/query_config.c
@@ -2762,6 +2762,14 @@
     }
 #endif /* MBEDTLS_SSL_COOKIE_TIMEOUT */
 
+#if defined(MBEDTLS_TLS_EXT_CID)
+    if( strcmp( "MBEDTLS_TLS_EXT_CID", config ) == 0 )
+    {
+        MACRO_EXPANSION_TO_STR( MBEDTLS_TLS_EXT_CID );
+        return( 0 );
+    }
+#endif /* MBEDTLS_TLS_EXT_CID */
+
 #if defined(MBEDTLS_X509_MAX_INTERMEDIATE_CA)
     if( strcmp( "MBEDTLS_X509_MAX_INTERMEDIATE_CA", config ) == 0 )
     {