bug#36832: Supply option to suppress scrolling in compilation mode buffers.

["Mattias Engdegård" <mattiase@acm.org>]

After 29d1c72d7c, next-error and previous-error no longer work as before in compilation-mode.
The fringe arrow is often not moved at all until the compilation window is made active, and the cursor in that buffer isn't moved at all; scrolling never occurs. This is with a plain NS build on macOS 10.14, compilation-context-lines being nil (the default).

When compilation-context-lines is set to an integer, it seems to work normally.

In compilation-set-window, the expression

    (set-window-point w mk)

was previously executed unconditionally if compilation-context-lines was not an integer; now, it is only run if there is no left fringe. The following change restores previous behaviour in that respect:

@@ -2600,7 +2600,8 @@ compilation-set-window
                                (goto-char mk)
                               (beginning-of-line 1)
                               (point)))
-         (set-window-point w mk))))
+         (set-window-point w mk))
+        (t (set-window-point w mk))))

but you probably want to reformulate the code to avoid duplication.