Fix build for GLES < 3.2

[zorn-v]

If you try to build with -DENABLE_OPENGL=ON -DOPENGL_PROFILE=OpenGLES3 you'll get several
error: 'glObjectLabel' was not declared in this scope; did you mean 'glObjectLabelKHR'?

It appears only in 3.2

$ grep glObjectLabel /usr/include/GLES3/*
/usr/include/GLES3/gl32.h:GL_APICALL void GL_APIENTRY glObjectLabel (GLenum identifier, GLuint name, GLsizei length, const GLchar *label);

As it used only for debug purposes I just dummy it out in that case.
Maybe need to do something better like using glObjectLabelKHR (defined in GLES2/gl2ext.h) as supposed.

[JesseTG]

Thank you for the contribution. Could you please submit this change against dev rather than main?

[JesseTG]

Hm...now that I think about it, I'm not sure that this change is necessary, because melonDS doesn't support OpenGL ES. I've already tried, the shaders don't work. Is there something you're trying to accomplish by building the core against OpenGL ES?

[zorn-v]

I tried it for rasPI4b, but no luck, yes )
Maybe just remove/comment that OpenGLES profiles for now to not confuse anyone ?

[JesseTG]

I tried it for rasPI4b, but no luck, yes ) Maybe just remove/comment that OpenGLES profiles for now to not confuse anyone ?

I did that work before realizing that OpenGL ES wasn't supported upstream. I don't want to get rid of it entirely; if upstream gets OpenGL ES support then enabling it here will be that much simpler. However, I agree that a configure-time warning about this is a good idea. I have other things on my plate, but I'll accept a PR that adds a warning in CMake.

[zorn-v]

Maybe fatal error then ? There is no sense to continue building not working things )