Add <endian.h> back and stop building one tool for the Mac.

We can't stop building all this stuff until we clean up the build
system to not require the OTA tools on Mac OS. This code does actually
use htobe64 and so should have included <endian.h>, so put that back.

Change-Id: I2807b4f237d3e26d470652f373f2de85864691c4
2 files changed