Log Message:
libuv: updated to 1.38.1

Changes since version 1.38.0:
* test: use last matching qemu version
* win, util: rearrange uv_hrtime
* test: skip signal_multiple_loops test on QEMU
* build: add android build to CI
* test: extend fs_event_error_reporting timeout
* build: link libkvm on netbsd only
* linux: refactor /proc file reader logic
* linux: read load average from /proc/loadavg
* android: remove patch code for below 21
* win: fix visual studio 2008 build
* win,tty: fix deadlock caused by inconsistent state
* unix: use relaxed loads/stores for feature checks
* build: don't .gitignore m4/ax_pthread.m4
* unix: fix gcc atomics feature check
* darwin: work around clock jumping back in time
* udp: fix write_queue cleanup on sendmmsg error
* src: build fix for Android