[GtkGLExt] API changes for the next major gtkglext release (glext)

[Arc Riley <ArcRiley pysoy org>]

I argue that the glext should remain and be expanded to fully replace GLEW/GLee.

There is no license issue.  GLEW is under the BSD, at worse you include the BSD boilerplate in the header and copy/modify their headers.  It's fully compatible with both v2 and v3 of the LGPL.

More importantly, GLEW and gtkglext overlap in more ways than glext.h.  There's enough dependency bloat in the Gnome community, not to mention redundant functionality taking up valuable memory and causing cache misses that hurt performance.  GLEW is barely enough to constitute a full library in any event.  That's one less dependency to worry about.

A third and trivial issue is that GLEW is an immature library on GNU/Linux, a really basic build system (static makefiles that break if the GL headers are not where they're expected) and no pkg-config file.  GLee even moreso, it's not even packaged in most distros.  It's a headache for upstream packages to configure and build with them and really unnecessary given gtkglext already providing much of the platform agnosticism GLEW is commonly used for.

I'm volunteering to expand gtkglext to fully replace GLEW.  It'd be less work for me than continuing to use GLEW in our engine.