As suggested by Joshua, this commit adds the 2-clause BSD license as a
comment block to the top of every source file.
For the first pass, I've just added myself for simplicity. I encourage
everyone to add themselves as copyright holders of any file they've
added or modified in some significant way. If I've added myself in
error somewhere, feel free to replace it with the appropriate copyright
holder instead.
Going forward, all new source files should include a license header.
Now that the kernel supports thread-local storage, we can declare errno
with the __thread keyword, which causes it to be per-thread.
This should fix all the stupid issues that happen when many threads use
the same errno. :^)
