all: merge master into release-branch.go1.7
7a62274 net/http: make Transport use new connection if over HTTP/2 concurrency limit
219ca60 doc: fix required OS X version inconsistency for binary downloads
26015b9 runtime: make stack 16-byte aligned for external code in _rt0_amd64_linux_lib
9fde86b runtime, syscall: fix kernel gettimeofday ABI change on iOS 10
3a03e87 os: check for waitid returning ENOSYS
1031675 net/http: update bundled http2 for flow control window adjustment fix
da070be syscall: fix Gettimeofday on macOS Sierra
f135c32 runtime: initialize hash algs before typemap
Change-Id: Ie176f3db1e253d75ae8e56b16d3fd9900b37dde3