wireguard: bump to 0.0.20181119

wireguard: bump to 0.0.20181119

* chacha20,poly1305: fix up for win64
* poly1305: only export neon symbols when in use
* poly1305: cleanup leftover debugging changes
* crypto: resolve target prefix on buggy kernels
* chacha20,poly1305: don't do compiler testing in generator and remove xor helper
* crypto: better path resolution and more specific generated .S
* poly1305: make frame pointers for auxiliary calls
* chacha20,poly1305: do not use xlate

This should fix up the various build errors, warnings, and insertion errors
introduced by the previous snapshot, where we added some significant
refactoring. In short, we're trying to port to using Andy Polyakov's original
perlasm files, and this means quite a lot of work to re-do that had stableized
in our old .S.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
(backported from 48d8d46d331cd866ad5717cc5b090223a1856a4a)