Auto merge of #1947 - fornwall:android-lockf-operations, r=JohnTitor
Auto merge of #1947 - fornwall:android-lockf-operations, r=JohnTitor

Add lockf() operations to Android

Reference:
https://github.com/aosp-mirror/platform_bionic/blob/master/libc/include/bits/lockf.h#L39-L46

rust-lang/libc,rust-lang/libc,rust-lang/libc