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.
diff --git a/src/proto/window.pro b/src/proto/window.pro
index d82988e..8b649db 100644
--- a/src/proto/window.pro
+++ b/src/proto/window.pro
@@ -56,6 +56,7 @@
 void win_drag_vsep_line(win_T *dragwin, int offset);
 void set_fraction(win_T *wp);
 void win_new_height(win_T *wp, int height);
+void scroll_to_fraction(win_T *wp, int prev_height);
 void win_new_width(win_T *wp, int width);
 void win_comp_scroll(win_T *wp);
 void command_height(void);