[release-branch.go1.8] all: merge master into release-branch.go1.8
6593d8650d go/ast: fix Object's doc comment about Data
c1730ae424 runtime: force workers out before checking mark roots
d10eddcba3 testing: make parallel t.Run safe again
2c8b70eacf crypto/x509: revert SystemCertPool implementation for Windows
fcfd91858b doc/go1.8: document Plan 9 requirements
81a61a96c9 runtime: for plugins, don't add duplicate itabs
f674537cc9 README.md: update and simplify
d8711919db cmd/go: fix bug help message
48d8edb5b2 crypto/tls: disable CBC cipher suites with SHA-256 by default
92ecd78933 cmd/compile: add ZeroWB case in writebarrier
787125abab doc: 2017 is the Year of the Gopher
5b708a6b6a cmd/compile: lvalues are only required for == when calling runtime fns
e83d506714 vendor/golang_org/x/crypto/poly1305: revendor to pick up fix for #18673
76f981c8d8 net/http: skip TestServerHijackGetsBackgroundByte on Plan 9
e395e3246a net/http: skip TestServerHijackGetsBackgroundByte_big on Plan 9
6a3c6c0de8 net/http: add another hijack-after-background-read test
467109bf56 all: test adjustments for the iOS builder
b2a3b54b95 net/http: make sure Hijack's bufio.Reader includes pre-read background byte
593ea3b360 cmd/go, misc: rework cwd handling for iOS tests
0642b8a2f1 syscall: export Fsid.X__val on s390x
4601eae6ba doc/gdb: mention GOTRACEBACK=crash
4c4c5fc7a3 misc/cgo/testplugin: test that types and itabs are unique
22689c4450 reflect: keep makeFuncImpl live across makeFuncStub
9cf06ed6cd cmd/link: only exclude C-only symbols on darwin
9c3630f578 compress/flate: avoid large stack growth in fillDeflate
4f0aac52d9 cmd/go: add comment about SIGUSR2 on iOS
333f764df3 cmd/go, misc: switch from breakpoint to SIGUSR2
39e31d5ec0 doc/go1.8: update timezone database version
08da8201ca misc/cgo/testshared: test that types and itabs are unique
fdde7ba2a2 runtime: avoid clobbering C callee-save register in cgoSigtramp
f65abf6ddc cmd/compile: hide testdclstack behind debug flag
641ef2a733 compress/gzip: skip TestGZIPFilesHaveZeroMTimes on non-builders
0724aa813f crypto/dsa: gofmt
ac05542985 net/http: deflake TestRetryIdempotentRequestsOnError
b842c9aac7 doc: remove inline styles
Change-Id: I642c056732fe1e8081e9d73e086e38ea0b2568cc