glCreateShader(GL_TESS_CONTROL_SHADER) causes glGetError()=INVALID_ENUM

Greetings,

This is my first post here, and I'm totally green with Mesa/
OpenGL. So, I'm not certain if this is the proper list for my
question(s). Feel free to direct me elsewhere in that case.
I was hoping to lurk for some time before posting, but the
list seems pretty quiet.

I'm trying to wrap my head around all the terminology,
different libraries, versions, etc. It's all a bit overwhelming
to a newbie.

With that introduction ...

Is it expected that GLenum types are defined for "future"
versions GL versions? e.g., GL_TESS_CONTROL_SHADER
and GL_TESS_EVALUATION_SHADER require GL 4.0, yet,
are defined in GL/glext.h.

This leads to confusion, when the source code making
use of said GLenum compiles, but fails at runtime.

Or am I completely confused and doing things the way
not meant to be done?

Appreciate any direction/advice from seasoned folks.

Best,
--patrick