d/patches: Add patch to disable hardware acceleration

It seems to be broken with recent versions of WebKitGTK, especially on X11. Needs further testing and possibly a bug report against WebKit itself.

This is how it is currently fixed in the upstream version of devhelp: https://gitlab.gnome.org/GNOME/devhelp/-/commit/e6c644683fbb34ac4ceb31150ef20a2536512149

https://phabricator.apertis.org/T9292

debian/patches/Disable-hardware-acceleration.patch

+From: Emmanuele Bassi <ebassi@gnome.org>
+Date: Wed, 13 Jul 2022 20:08:47 +0100
+Subject: Disable hardware acceleration
+Origin: https://gitlab.gnome.org/GNOME/devhelp/-/commit/e6c644683fbb34ac4ceb31150ef20a2536512149
+
+It seems to be broken with recent versions of WebKitGTK, especially on
+X11. Needs further testing and possibly a bug report against WebKit
+itself.
+
+Fixes: #60
+---
+ devhelp/dh-web-view.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/devhelp/dh-web-view.c b/devhelp/dh-web-view.c
+index 8c1ca9b..a8230a0 100644
+--- a/devhelp/dh-web-view.c
++++ b/devhelp/dh-web-view.c
+@@ -480,6 +480,7 @@ dh_web_view_constructed (GObject *object)
+ 
+         webkit_settings = webkit_web_view_get_settings (WEBKIT_WEB_VIEW (view));
+         webkit_settings_set_enable_back_forward_navigation_gestures (webkit_settings, TRUE);
++        webkit_settings_set_hardware_acceleration_policy (webkit_settings, WEBKIT_HARDWARE_ACCELERATION_POLICY_NEVER);
+ 
+         /* Disable some things we have no need for. */
+         webkit_settings_set_enable_html5_database (webkit_settings, FALSE);