Changes in ieee80211.h - How to?

I'm in a college project and I need to make some changes to the file include/ieee80211.h. But I do not find this file in Openwrt sources.
I would like to know what would be the way for me to make the change I need and thus recompile Openwrt/LEDE.

Thank you.

PS: I'm Brazilian, I'm sorry for the bad English.

kernel sources, along with many other sources, are retrieved at build time.

Patches are the typical way that files are changed/added/removed from "upstream" sources.

For kernel patches, some examples can be found with

find target/linux -name '*.patch'

Ok, thanks Jeff for the feedback.

So, even though I do not have the original file (ieee80211.h) in the sources, if I create and apply a patch to that file, will it work?

Thank you.

If you do a "plain vanilla" build for your target device, you should find the "original" sources in the build directory. You can create a patch against those.