mbed-os is a directory that gets checked out by the mbed cli
(a tool similar in spirit to miot) and it contains a lot of
.c sources, so many of them that clang-format burns your CPU.
While we're at it, also fix check_no_ifdefs when running under a commit
hook.
PUBLISHED_FROM=e5dd457ea3c4f9bd880f2491fb322dffa7abf70a
Identifiers starting with _ are reserved, fix those.
Wrote a tool to do it and applied it globally, why not.
PUBLISHED_FROM=db0fa27c90cbfb06ed06469406f9867c5a5bd3c4
