Qt Error: 'non-portable path' to 'gl/GLU.h' - Case Sensitivity Issue

The error message 'Qt non-portable path to file 'gl/GLU.h'; specified path differs in case from file name on disk' indicates a mismatch between the case of the file path you provided in your code and the actual case of the file name on disk. This is due to case-sensitive file systems.

To fix this issue, follow these steps:

1. Check the actual file name case: Verify the exact case (uppercase and lowercase) of the file 'GLU.h' on your disk. Ensure it matches the path used in your code.

2. Update the path in your code: Once you've confirmed the correct case, update the path in your code to match it. For example, if the correct case is 'GLU.h' and it's located in the 'gl' directory, use:

#include <gl/GLU.h>

3. Rebuild your project: After updating the path, rebuild your project to ensure the changes are applied. This will confirm if the error is resolved.

By following these steps, you should be able to resolve the 'non-portable path' error and successfully include the 'gl/GLU.h' file in your Qt project.