Squashed 'external/libuv/' content from commit 717e0e5

git-subtree-dir: external/libuv
git-subtree-split: 717e0e5635a03ab2b1366e3ff2015ad223855b81
Merge commit 'c9030e0ec8b5f3438461b74bd9e645f8850a0c59' as 'external/libuv'