wireguard: bump to 0.0.20181007

wireguard: bump to 0.0.20181007

64750c1 version: bump snapshot
f11a2b8 global: style nits
4b34b6a crypto: clean up remaining .h->.c
06d9fc8 allowedips: document additional nobs
c32b5f9 makefile: do more generic wildcard so as to avoid rename issues
20f48d8 crypto: use BIT(i) & bitmap instead of (bitmap >> i) & 1
b6e09f6 crypto: disable broken implementations in selftests
fd50f77 compat: clang cannot handle __builtin_constant_p
bddaca7 compat: make asm/simd.h conditional on its existence
b4ba33e compat: account for ancient ARM assembler

Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
(backported from 3925298f3ca9bcd854571367d98bb6ca07f4e66e)