According to those slides by nvidia (slide 24), there seems to be some kind of include directives in recent opengl / glsl.
According to the wiki, this does not seem true : "[...]. The most notable omission is #include."
So, who is right here ? If I should do this by myself or not is not the question, I just want precisions about what NVidia seemed to claim during this presentation.
This is a misrepresentation from NVIDIA about what's going on. For some reason, NVIDIA has decided to present extension-only functionality right alongside core functionality, without any statements about what parts are extension-only.
What this slide is referring to is ARB_shading_language_include, an OpenGL extension that has not be incorporated into any version of OpenGL. Indeed, if this database is accurate, then the only implementations of OpenGL that expose this extension are written by NVIDIA.
So if you use this feature, you're tying yourself to NVIDIA's hardware.