Compat: Check for successful GLEW initialisation fails on my PC / Trixie

I observed same strange behaviour already last year on my »Video Output« talk.
The return value indicates an unkown error, but the subsequent usage seemingly works...

On my Laptop, I don not see this error; it might be due to the very old graphics card on my PC...

FrOSCon26/examples/README

@@ -5,15 +5,12 @@ IO_URING and Video Output Example Code
 :date: 8/2026
 
 
-This directory contains a example code to demonstrate reading data blocks
+This directory contains example code to demonstrate reading data blocks
 continuously using the io_uring kernel interface. The loaded data is then
 fed to a video display pipeline based on OpenGL / EGL
 
-[red yellow-background]#Publish on Lumiera.org#
-////
 TIP: This demo code has been published on
-     link:https://lumiera.org/research/videoDisplay/index.html[Lumiera.org]
+     link:https://www.lumiera.org/research/ioUring/index.html[Lumiera.org]
-////
 
 
 Building the code
@@ -39,9 +36,9 @@ TIP: The `-j4` option tells make to use 4 cores concurrently to speed up the bui
 Use at least GCC-14
 ~~~~~~~~~~~~~~~~~~~
 [red yellow-background]#TODO: still relevant?#
-Some older C++ compilers seem to have problems with a `constexpr` function used in 'commons.hpp'.
+Some older C++ compilers seem to have problems with `constexpr` functions;
-Either comment out the line with the static assertion, or use at least GCC-14, which can be
+to circumvent such problems, you might want to use at least GCC-14,
-configured for CMake with
+which can be configured for CMake with
 
 -----
 cmake -S examples -B build -DCMAKE_CXX_COMPILER=g++-14

FrOSCon26/examples/egl-display.hpp

@@ -183,9 +183,10 @@ EglDisplay<PIX,WIDTH,HEIGHT>::openDisplay (Gtk::Window& appWindow)
 
   // use lib-GLEW to manage OpenGL extensions (notably GL Shader Language)
   GLenum glewErr = glewInit();
-  if (GLEW_OK != glewErr)
+////////////////////////////////////////////////////////////////////////////////////TODO for some reason I get glewErr == 4 ("unknown error"), but it works non the less
-    __FAIL ("could not bind OpenGL extensions through lib-GLEW:\n"
+//if (GLEW_OK != glewErr)
-           +string{reinterpret_cast<const char*> (glewGetErrorString(glewErr))});
+//  __FAIL ("could not bind OpenGL extensions through lib-GLEW:\n"
+//         +string{reinterpret_cast<const char*> (glewGetErrorString(glewErr))});
 
 
   auto compileShader = [](GLenum kind, string code)