Draft: AmigaOS4: Add support for this platform
This MR adds support for the AmigOS4 platform to CMAKE:
- Added general platform definition for AmigaOS4
- Added AmigaOS4 C and CXX compiler-specific configuration
- Updated FindOpenGL.cmake to support AmigaOS4
- Added documentation for AmigaOS4 in FindOpenGL.cmake
- Added defines that show what OpenGL implementation is selected
Fixes: #25736
Topic-rename: amigaos4-platform
Edited by Brad King