platform macros with (ternary operator) else clauses, of the form `@windows? a : b`
Merge pull request #3844 from JuliaLang/jn/platform_specific

better platform macros, with ternary behavior
Fix libuv bump

Revert "Revert "Update libuv""

This reverts commit a72e8a521e331e8c0017211afb9f2ca34fd9ee45.

Revert "Revert libuv bumps"

This reverts commit 1a08064328db54e4c78c90aecdd06846449514ff.
Close #3849
Merge branch 'master' of github.com:JuliaLang/julia