Upstream assumes gnu99 (and has been dead for years). am: d4084d1400

Original change: https://android-review.googlesource.com/c/platform/external/cn-cbor/+/3368618

Change-Id: I66f24564298303e88d7bcb438994dc2500235e57
Signed-off-by: Automerger Merge Worker <[email protected]>