bug#35204: 27.0.50; Crash on Cygwin

[Ken Brown <kbrown@cornell.edu>]

On 4/12/2019 3:11 AM, Eli Zaretskii wrote:
> Ken, could you please chime in?  It is strange that this problem only
> affects the Cygwin build, and no other bug report points to that
> change from other GTK builds

Sorry for not chiming in sooner.  I saw the bug report but was busy with other 
things.

I can replicate the crash on my system, but reverting only a tiny part of the 
commits in question seems to fix it, in the sense that I can successfully 
evaluate x-display-monitor-attributes-list:

diff --git a/src/xfns.c b/src/xfns.c
index 13f66f0718..3e4d037716 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -5030,7 +5030,7 @@ Internal use only, use `display-monitor-attributes-list' 
instead.  */)
        mi->mm_height = height_mm;

  #if GTK_CHECK_VERSION (3, 22, 0)
-      mi->name = xstrdup (gdk_monitor_get_model (monitor));
+      mi->name = g_strdup (gdk_monitor_get_model (monitor));
  #elif GTK_CHECK_VERSION (2, 14, 0)
        mi->name = gdk_screen_get_monitor_plug_name (gscreen, i);
  #endif

I don't know enough about GTK to know why this fixes it or why no one else has 
reported the problem.  It's hard to see why this would be specific to Cygwin.

Ken