CGraphicsBackend_SDL_OpenGL::Init
could you try adding these lines before the context is created, and send a compiled client to that guy from the forum:
SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
i saw that the pixel alignment function exists since OpenGL 2.0, the text renderer uses it, and the screenshot function uses it. Theoretically, the AMD driver would be allowed to fail this function, if it really creates an older context than 2.0
since there is no GPU outside that uses less than 2.0 (https://opengl.gpuinfo.org/) and since the screenshot function used it always anyway, it's safe to assume the minimum required OpenGL version must be 2.0 anyway.
Also @n000b said the text was ok with GL3.3(even if other stuff was driver related buggy), so there is a huge chance that this might work.
And in your words, let's try and see xd