Upstream: https://github.com/xiph/libopusenc.git
Version:  0.3 (tag v0.3, commit 0dba1bea736ab8bb811409dce80c994a00a2ced9)

Vendored by vendor.py in the parent directory; rerun it to update. It copies
the .c files the unity translation units compile and every header reachable
from them, and rewrites their includes as paths relative to the including
file.
