From f0818c6725cf85329755d0675643fa4e7ec4a018 Mon Sep 17 00:00:00 2001
From: Martin Reboredo <yakoyoku@gmail.com>
Date: Sun, 30 Jan 2022 20:08:03 -0300
Subject: [PATCH] Fix build failure in #764

---
 Gui/Gui.pro           | 9 +++++++--
 Gui/GuiFwd.h          | 5 ++++-
 Gui/ViewerGLPrivate.h | 4 ++++
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/Gui/Gui.pro b/Gui/Gui.pro
index bda80d9691..0d27bb0b80 100644
--- a/Gui/Gui.pro
+++ b/Gui/Gui.pro
@@ -22,8 +22,13 @@ TEMPLATE = lib
 CONFIG += staticlib
 CONFIG += moc rcc
 CONFIG += boost opengl qt cairo python shiboken pyside 
-QT += gui core opengl network
-greaterThan(QT_MAJOR_VERSION, 4): QT += concurrent
+QT += gui core network
+
+greaterThan(QT_MAJOR_VERSION, 4) {
+    QT += concurrent
+} else {
+    QT += opengl
+}
 
 GUI_WRAPPER_DIR = Qt$${QT_MAJOR_VERSION}/NatronGui
 ENGINE_WRAPPER_DIR = Qt$${QT_MAJOR_VERSION}/NatronEngine
diff --git a/Gui/GuiFwd.h b/Gui/GuiFwd.h
index 511c16f9aa..d9e127abad 100644
--- a/Gui/GuiFwd.h
+++ b/Gui/GuiFwd.h
@@ -49,7 +49,6 @@ class QFont;
 class QFontComboBox;
 class QFontMetrics;
 class QFrame;
-class QOpenGLShaderProgram;
 class QGraphicsLineItem;
 class QGraphicsPolygonItem;
 class QGraphicsScene;
@@ -95,6 +94,10 @@ class QWheelEvent;
 class QWidget;
 typedef boost::shared_ptr<QUndoStack> QUndoStackPtr;
 
+#if QT_VERSION >= QT_VERSION_CHECK(5, 4, 0)
+class QOpenGLShaderProgram;
+#endif
+
 // Natron Gui
 NATRON_NAMESPACE_ENTER
 class AboutWindow;
diff --git a/Gui/ViewerGLPrivate.h b/Gui/ViewerGLPrivate.h
index d89cf0ccb9..78eca6b118 100644
--- a/Gui/ViewerGLPrivate.h
+++ b/Gui/ViewerGLPrivate.h
@@ -42,6 +42,10 @@ CLANG_DIAG_ON(uninitialized)
 #include "Gui/ZoomContext.h"
 #include "Gui/GuiFwd.h"
 
+#if QT_VERSION < QT_VERSION_CHECK(5, 4, 0)
+#include "Gui/QGLExtrasCompat.h"
+#endif
+
 
 #define WIPE_MIX_HANDLE_LENGTH 50.
 #define WIPE_ROTATE_HANDLE_LENGTH 100.