patch 7.4.2279

Problem:    Starting diff mode with the cursor in the last line might end up
            only showing one closed fold. (John Beckett)
Solution:   Scroll the window to show the same relative cursor position.

src/diff.c

@@ -1075,6 +1075,10 @@ ex_diffsplit(exarg_T *eap)
 #ifdef FEAT_GUI
     need_mouse_correct = TRUE;
 #endif
+    /* Need to compute w_fraction when no redraw happened yet. */
+    validate_cursor();
+    set_fraction(curwin);
+
     /* don't use a new tab page, each tab page has its own diffs */
     cmdmod.tab = 0;
 
@@ -1101,6 +1105,9 @@ ex_diffsplit(exarg_T *eap)
 			    curbuf,
 			    curwin->w_cursor.lnum);
 	    }
+	    /* Now that lines are folded scroll to show the cursor at the same
+	     * relative position. */
+	    scroll_to_fraction(curwin, curwin->w_height);
 	}
     }
 }