stb_image inconsistencies

stb_image is used to load images in various example/* and demo/* examples.

There's currently two different stb_image versions, where example/stb_image.h is v2.08 and demo/common/filebrowser/stb_image.h is v2.28.

stb_image also isn't compatible with C89 because of the C++ style comments.

Would it make sense to create a single stb_image file with the latest version (2.30) that is compatible with C89?