patch 7.4.975

Problem:    Using ":sort" on a very big file sometimes causes text to be
            corrupted. (John Beckett)
Solution:   Copy the line into a buffer before calling ml_append().

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    975,
 /**/
     974,
 /**/