These are not provided by standards, and as a result causes failure to
compile on musl.

https://wiki.musl-libc.org/faq.html#Q:-When-compiling-something-against-musl,-I-get-error-messages-about-%3Ccode%3Esys/cdefs.h%3C/code%3E

Change-Id: I6a357cefd106c72cfecafd898638f6b5692c2e05