Remove erroneous widget dependency for hellogles3

Change-Id: I42b476be28acd5b5c68f115bd98cf5c43cd8d97b
Reviewed-by: Christian Strømme <christian.stromme@qt.io>
(cherry picked from commit d0dc0477b9c0350a257b284a90a813b2b00d1543)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

examples/opengl/CMakeLists.txt

@@ -2,6 +2,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 
 qt_internal_add_example(openglwindow)
+qt_internal_add_example(hellogles3)
 if(TARGET Qt6::Widgets)
     qt_internal_add_example(contextinfo)
     qt_internal_add_example(2dpainting)
@@ -9,6 +10,5 @@ if(TARGET Qt6::Widgets)
     qt_internal_add_example(qopenglwidget)
     qt_internal_add_example(cube)
     qt_internal_add_example(textures)
-    qt_internal_add_example(hellogles3)
     qt_internal_add_example(stereoqopenglwidget)
 endif()

examples/opengl/hellogles3/doc/src/hellogles3.qdoc

@@ -18,5 +18,11 @@
       \li The shader code's version directive is different.
     \endlist
 
+    This example has no QWidget dependencies. Instead, it uses QOpenGLWindow, a
+    convenience subclass of QWindow that allows easy implementation of windows
+    that contain OpenGL-rendered content. In this sense it complements the
+    \l{OpenGL Window Example}, which shows the implementation of an OpenGL-based
+    QWindow without using the convenience subclass.
+
     \image hellogles3-example.png
 */

examples/opengl/opengl.pro

@@ -1,6 +1,7 @@
 TEMPLATE      = subdirs
 
-SUBDIRS = openglwindow
+SUBDIRS = openglwindow \
+          hellogles3
 
 qtHaveModule(widgets) {
     SUBDIRS += contextinfo \
@@ -9,6 +10,5 @@ qtHaveModule(widgets) {
                qopenglwidget \
                cube \
                textures \
-               hellogles3 \
                stereoqopenglwidget
 }