From 3e0d5577444b32579bdf5b69d720a322322ff7bc Mon Sep 17 00:00:00 2001
From: Milian Wolff <milian.wolff@kdab.com>
Date: Tue, 26 Nov 2019 15:08:20 +0100
Subject: [PATCH] qmlgl: ensure Qt defines GLsync to fix compile on some
 platforms
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By explictly including QtGui/qopengl.h we force the code path that
defines GLsync in the Qt-specific way. Without that, some platforms
failed to compile the qmlgl plugin, since neither Qt nor gstreamer
defined GLsync then, leading to e.g.:

```
make[4]: Entering directory '/.../gst-plugins-good-1.16.1/ext/qt'
  CXX      libgstqmlgl_la-qtitem.lo
In file included from gstqtgl.h:32,
                 from qtitem.h:27,
                 from qtitem.cc:28:
/.../usr/include/gstreamer-1.0/
gst/gl/gstglfuncs.h:93:17: error: expected identifier before ‘*’ token
   ret (GSTGLAPI *name) args;
                 ^
/.../usr/include/gstreamer-1.0/
gst/gl/glprototypes/sync.h:27:1: note: in expansion of macro
‘GST_GL_EXT_FUNCTION’
 GST_GL_EXT_FUNCTION (GLsync, FenceSync,
 ^~~~~~~~~~~~~~~~~~~
```
---
 ext/qt/gstqtgl.h | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/ext/qt/gstqtgl.h b/ext/qt/gstqtgl.h
index 4d0bb64c11..a1babaad18 100644
--- a/ext/qt/gstqtgl.h
+++ b/ext/qt/gstqtgl.h
@@ -22,14 +22,7 @@
 #include <QtGui/qtgui-config.h>
 #endif
 
-/* qt uses the same trick as us to typedef GLsync on GLES2 but to a different
- * type which confuses the preprocessor. Instead of trying to reconcile the
- * two, we instead use the GLsync definition from Qt from above, and ensure
- * that we don't typedef GLsync in gstglfuncs.h */
 #include <gst/gl/gstglconfig.h>
-#undef GST_GL_HAVE_GLSYNC
-#define GST_GL_HAVE_GLSYNC 1
-#include <gst/gl/gstglfuncs.h>
 
 /* The glext.h guard was renamed in 2018, but some software which
  * includes their own copy of the GL headers (such as qt) might have
@@ -46,6 +39,17 @@
 #endif
 #endif
 
+/* pulls in GLsync, see below */
+#include <QtGui/qopengl.h>
+
+/* qt uses the same trick as us to typedef GLsync on GLES2 but to a different
+ * type which confuses the preprocessor. Instead of trying to reconcile the
+ * two, we instead use the GLsync definition from Qt from above, and ensure
+ * that we don't typedef GLsync in gstglfuncs.h */
+#undef GST_GL_HAVE_GLSYNC
+#define GST_GL_HAVE_GLSYNC 1
+#include <gst/gl/gstglfuncs.h>
+
 #if defined(QT_OPENGL_ES_2)
 #include <QtGui/QOpenGLContext>
 #include <QtGui/QOpenGLFunctions>