emacs-31 def15c1b973: Disable DMABUF and Compositing for xwidget

branch: emacs-31
commit def15c1b973e17b98c39684b06646f521497ae52
Author: Dirk-Jan C. Binnema <[email protected]>
Commit: Eli Zaretskii <[email protected]>

    Disable DMABUF and Compositing for xwidget
    
    Webkit does not support DMABUF or accelerated compositing in the
    offscreen widgets Emacs uses for xwidget.  Disable both for non-pgtk
    GTK3 builds (Bug#80834).
    * src/xterm.c (init_xterm): Set WEBKIT_DISABLE_DMABUF_RENDERER and
    WEBKIT_DISABLE_COMPOSITING_MODE when built with xwidgets and not pgtk.
    
    Copyright-paperwork-exempt: yes
---
 src/xterm.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/xterm.c b/src/xterm.c
index 1401693541c..d95de2ef86b 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -32364,6 +32364,13 @@ static struct textconv_interface text_conversion_interface =
 void
 init_xterm (void)
 {
+#if defined(HAVE_XWIDGETS) && !defined(HAVE_PGTK)
+  /* Emacs uses off-screen gtk widgets for webkit views, which do not support
+     DMABUF or Compositing Mode; webkit aborts unless we disable those.  */
+    xputenv ("WEBKIT_DISABLE_DMABUF_RENDERER=1");
+    xputenv ("WEBKIT_DISABLE_COMPOSITING_MODE=1");
+#endif
+
 #ifndef HAVE_XINPUT2
   /* Emacs can handle only core input events when built without XI2
      support, so make sure Gtk doesn't use Xinput or Xinput2