Squashed 'third_party/poco_1.5.3/' content from commit cd607b6

git-subtree-dir: third_party/poco_1.5.3
git-subtree-split: cd607b6f28908526677246dbcc5f76cf1d6617e6
Merge commit '86d034c52ad01740d2e58c51b688d7f2ffb76168' as 'third_party/poco_1.5.3'