clang-format libc string functions imported from musl

[emaste]

Summary

We have adopted these and don't consider them 'contrib' code.

[emaste]

lib/libc/string/strcspn.c

31–32

splitting between the 1 and << seems confusing

[emaste]

I much prefer the formatted version, except perhaps for the BITOP macro.

We have adopted these functions; changes from musl, if any, would be manually applied if this change goes in.
OpenBSD also imported some musl string routines and reformatted them.

[arichardson]

lib/libc/string/strcspn.c

31–32

Seems like clang-format assumes that op( is a function call and then the formatting for the rest of the line is broken.
It might also like breaking before << because of LLVM's streaming I/O classes where that formatting does make sense.