Add option to exclude Khronos platform code
In generated Glad 2 headers, there are a few hundred lines of code prefixed with khronos_ or KHRONOS_, none of which I use in my projects. Some of the khronos_ types directly translate to GL types and could be replaced with standard C/C++ types instead.

I recall that in the past, Glad had an option to exclude the Khronos code. It would be nice to have that feature.