Add necessary build flags and switch from using a GLES2 context to a GLES3 one. This also enables building for OpenXR Co-authored-by: m4gr3d <fhuyakou@gmail.com> Co-authored-by: dsnopek <dsnopek@gmail.com>
- Use gl.h provided by GLAD in the OpenXR module - Use non-EXT variants of some OpenGL defines - Remove libGL-related code paths
