bug#38822: 27.0.60; Crashes on MacOS 10.14 when quitting emacs, and intermittent crashes during normal usage

[Robert Pluim]

>>>>> On Fri, 17 Jan 2020 12:10:24 -0600, Justin Guenther <jguenther@gmail.com> 
>>>>> said:

    Justin> On Tue, Dec 31, 2019 at 12:39 PM Eli Zaretskii <eliz@gnu.org> wrote:
    >> 
    >> 3 months went under the bridge between these two commits, so it's hard
    >> to tell which change caused that.  But there's a similar bug report at
    >> https://debbugs.gnu.org/cgi/bugreport.cgi?bug=38748.

    Justin> I think this is indeed a dupe of 38748, this patch seems to have 
fixed
    Justin> this crash for me:
    Justin> https://debbugs.gnu.org/cgi/bugreport.cgi?bug=38748#92

Thanks for that. Eli, should we apply this to emacs-27 with
attribution to Pip Cet?:

diff --git a/src/nsterm.m b/src/nsterm.m
index 03754e5ae5..c1d1d41117 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -1644,6 +1644,7 @@ Hide the window (X11 semantics)
   [view release];
 
   xfree (f->output_data.ns);
+  f->output_data.ns = NULL;
 
   unblock_input ();
 }