Don't explicitly set LOCAL_CLANG for host.

Clang is already the default for host builds on Linux and Darwin, and
setting this forces Windows to clang as well, which isn't supported
yet.

Clean up the now redundant LOCAL_ADDITIONAL_DEPENDENCIES while I'm
here.

Change-Id: I24ee5144f40d10a2064ad12fb5e53c6bc791fe7c
1 file changed