patch 8.1.0360: using an external diff program is slow and inflexible commit https://github.com/vim/vim/commit/e828b7621cf9065a3582be0c4dd1e0e846e335bf Author: Bram Moolenaar <Bram@vim.org> Date: Mon Sep 10 17:51:58 2018 +0200 patch 8.1.0360: using an external diff program is slow and inflexible Problem: Using an external diff program is slow and inflexible. Solution: Include the xdiff library. (Christian Brabandt, closes https://github.com/vim/vim/issues/2732) Use it by default.

--- a/src/structs.h
+++ b/src/structs.h
@@ -2433,7 +2433,9 @@ struct file_buffer
     term_T	*b_term;	/* When not NULL this buffer is for a terminal
 				 * window. */
 #endif
-
+#ifdef FEAT_DIFF
+    int		b_diff_failed;	// internal diff failed for this buffer
+#endif
 }; /* file_buffer */