wireguard-tools: bump to 1.0.20200206

wireguard-tools: bump to 1.0.20200206

* wg-quick: android: split uids into multiple commands

Newer android's ndc implementations have limits on uid size, so we have to
break these into several lists.

* man: document dynamic debug trick for Linux

This comes up occasionally, so it may be useful to mention its
possibility in the man page. At least the Arch Linux and Ubuntu kernels
support dynamic debugging, so this advice will at least help somebody. So that
you don't have to go digging into the commit, this adds this helpful tidbit
to the man page for getting debug logs on Linux:

 # modprobe wireguard && echo module wireguard +p > /sys/kernel/debug/dynamic_debug/control

* extract-{handshakes,keys}: rework for upstream kernel

These tools will now use the source code from the running kernel instead of
from the old monolithic repo. Essential for the functioning of Wireshark.

* netlink: remove libmnl requirement

We no longer require libmnl. It turns out that inlining the small subset of
libmnl that we actually use results in a smaller binary than the overhead of
linking to the external library. And we intend to gradually morph this code
into something domain specific as a libwg emerges. Performance has also
increased, thanks to the inliner. On all platforms, wg(8) only needs a normal
libc. Compile time on my system is still less than one second. So all in all
we have: smaller binary, zero dependencies, faster performance.

Packagers should no longer have their wireguard-tools package depend on
libmnl.

* embeddable-wg-library: use newer string_list
* netlink: don't pretend that sysconf isn't a function

Small cleanups.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>