Include what you use: <unistd.h>

This was transitively included, but no longer is, so it must be
explicitly included.

Test: build
Bug: 157822244
Change-Id: Ifa85582c9380df6f16025eba86b64e9af32bc226
Merged-In: Ifa85582c9380df6f16025eba86b64e9af32bc226
2 files changed