The main advantage of SPDX license identifiers over the traditional
license headers is that it's more difficult to overlook inappropriate
licenses for kwin, for example GPL 3. We also don't have to copy a
lot of boilerplate text.
In order to create this change, I ran licensedigger -r -c from the
toplevel source directory.
The recommended way to get all EGL extension defines is to include
EGL/eglext.h. EGL/eglmesaext.h is a private header that compositors
should not use.
BUG: 422131