Created attachment 3274 [details]
Fix disabling SDL_GL_CONTEXT_DEBUG_FLAG for possibly faulty drivers

First of all, I'm sorry if the version I selected is incorrect. I'm using this mirror, which mirrors the "default" branch by default: https://github.com/spurious/SDL-mirror

When setting the SDL_GL_CONTEXT_DEBUG_FLAG context flag on my Android device powered by an Adreno 305 GPU, the window / context creation fails silently.

libEGL itself logs
 
    E/libEGL  (26984): validate_display:255 error 3008 (EGL_BAD_DISPLAY)

to logcat, but the window / context creation doesn't "fail" (it isn't returning NULL, nor setting an error) before crashing. Specifically, in this state, invoking any GL function obtained via SDL_GL_GetProcAddress, such as glGetString, immediately causes a segmentation fault.

Possibly related and worth noting: Even though neither the GL_KHR_debug nor the EGL_KHR_debug extensions are supported by my GPU, SDL_GL_GetProcAddress("glDebugMessageControlKHR") returns a stub which logs

    E/libEGL  (22431): called unimplemented OpenGL ES API

I've thus attached a diff which removes the SDL_GL_CONTEXT_DEBUG_FLAG flag before context creation if the EGL_KHR_debug extension isn't present and if the EGL version is lower than 1.5 (which supposedly includes the extension).
The patch makes SDL lie about the created context, but from what I can tell, this seems to be a driver-related bug in the first place.