cmd/api: add api/next.txt

This quiets all.bash noise for upcoming features we know about.

The all.bash warnings will now only print for things not in next.txt
(or in next.txt but not in the API).

Once an API is frozen, we rename next.txt to a new frozen file
(like go1.txt)

Fixes #3651

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6218069

api/README

+Files in this directory are data for Go's API checker ("go tool api", in src/cmd/api).
+
+Each file is a list of of API features, one per line.
+
+go1.txt (and similarly named files) are frozen once a version has been
+shipped. Each file adds new lines but does not remove any.
+
+next.txt is the only file intended to be mutated. It's a list of
+features that may be added to the next version. It only affects
+warning output from the go api tool.
+

api/next.txt

+pkg crypto/tls, const TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA uint16
+pkg crypto/tls, const TLS_RSA_WITH_AES_256_CBC_SHA uint16
+pkg crypto/x509, const ECDSA PublicKeyAlgorithm
+pkg crypto/x509, const ECDSAWithSHA1 SignatureAlgorithm
+pkg crypto/x509, const ECDSAWithSHA256 SignatureAlgorithm
+pkg crypto/x509, const ECDSAWithSHA384 SignatureAlgorithm
+pkg crypto/x509, const ECDSAWithSHA512 SignatureAlgorithm
+pkg debug/elf, type FileHeader struct, Entry uint64
+pkg go/doc, var IllegalPrefixes []string
+pkg math/big, method (*Int) MarshalJSON() ([]byte, error)
+pkg math/big, method (*Int) UnmarshalJSON([]byte) error
+pkg regexp/syntax, const ErrUnexpectedParen ErrorCode
+pkg syscall (darwin-386), const B0 ideal-int
+pkg syscall (darwin-386), const B110 ideal-int
+pkg syscall (darwin-386), const B115200 ideal-int
+pkg syscall (darwin-386), const B1200 ideal-int
+pkg syscall (darwin-386), const B134 ideal-int
+pkg syscall (darwin-386), const B14400 ideal-int
+pkg syscall (darwin-386), const B150 ideal-int
+pkg syscall (darwin-386), const B1800 ideal-int
+pkg syscall (darwin-386), const B19200 ideal-int
+pkg syscall (darwin-386), const B200 ideal-int
+pkg syscall (darwin-386), const B230400 ideal-int
+pkg syscall (darwin-386), const B2400 ideal-int
+pkg syscall (darwin-386), const B28800 ideal-int
+pkg syscall (darwin-386), const B300 ideal-int
+pkg syscall (darwin-386), const B38400 ideal-int
+pkg syscall (darwin-386), const B4800 ideal-int
+pkg syscall (darwin-386), const B50 ideal-int
+pkg syscall (darwin-386), const B57600 ideal-int
+pkg syscall (darwin-386), const B600 ideal-int
+pkg syscall (darwin-386), const B7200 ideal-int
+pkg syscall (darwin-386), const B75 ideal-int
+pkg syscall (darwin-386), const B76800 ideal-int
+pkg syscall (darwin-386), const B9600 ideal-int
+pkg syscall (darwin-386), const BRKINT ideal-int
+pkg syscall (darwin-386), const CFLUSH ideal-int
+pkg syscall (darwin-386), const CLOCAL ideal-int
+pkg syscall (darwin-386), const CREAD ideal-int
+pkg syscall (darwin-386), const CS5 ideal-int
+pkg syscall (darwin-386), const CS6 ideal-int
+pkg syscall (darwin-386), const CS7 ideal-int
+pkg syscall (darwin-386), const CS8 ideal-int
+pkg syscall (darwin-386), const CSIZE ideal-int
+pkg syscall (darwin-386), const CSTART ideal-int
+pkg syscall (darwin-386), const CSTATUS ideal-int
+pkg syscall (darwin-386), const CSTOP ideal-int
+pkg syscall (darwin-386), const CSTOPB ideal-int
+pkg syscall (darwin-386), const CSUSP ideal-int
+pkg syscall (darwin-386), const FLUSHO ideal-int
+pkg syscall (darwin-386), const HUPCL ideal-int
+pkg syscall (darwin-386), const ICANON ideal-int
+pkg syscall (darwin-386), const ICRNL ideal-int
+pkg syscall (darwin-386), const IEXTEN ideal-int
+pkg syscall (darwin-386), const IGNBRK ideal-int
+pkg syscall (darwin-386), const IGNCR ideal-int
+pkg syscall (darwin-386), const IGNPAR ideal-int
+pkg syscall (darwin-386), const IMAXBEL ideal-int
+pkg syscall (darwin-386), const INLCR ideal-int
+pkg syscall (darwin-386), const INPCK ideal-int
+pkg syscall (darwin-386), const ISIG ideal-int
+pkg syscall (darwin-386), const ISTRIP ideal-int
+pkg syscall (darwin-386), const IUTF8 ideal-int
+pkg syscall (darwin-386), const IXANY ideal-int
+pkg syscall (darwin-386), const IXOFF ideal-int
+pkg syscall (darwin-386), const IXON ideal-int
+pkg syscall (darwin-386), const NOFLSH ideal-int
+pkg syscall (darwin-386), const OCRNL ideal-int
+pkg syscall (darwin-386), const OFDEL ideal-int
+pkg syscall (darwin-386), const OFILL ideal-int
+pkg syscall (darwin-386), const ONLCR ideal-int
+pkg syscall (darwin-386), const ONLRET ideal-int
+pkg syscall (darwin-386), const ONOCR ideal-int
+pkg syscall (darwin-386), const ONOEOT ideal-int
+pkg syscall (darwin-386), const OPOST ideal-int
+pkg syscall (darwin-386), const PARENB ideal-int
+pkg syscall (darwin-386), const PARMRK ideal-int
+pkg syscall (darwin-386), const PARODD ideal-int
+pkg syscall (darwin-386), const PENDIN ideal-int
+pkg syscall (darwin-386), const TCIFLUSH ideal-int
+pkg syscall (darwin-386), const TCIOFLUSH ideal-int
+pkg syscall (darwin-386), const TCOFLUSH ideal-int
+pkg syscall (darwin-386), const TCSAFLUSH ideal-int
+pkg syscall (darwin-386), const TOSTOP ideal-int
+pkg syscall (darwin-386), const VDISCARD ideal-int
+pkg syscall (darwin-386), const VDSUSP ideal-int
+pkg syscall (darwin-386), const VEOF ideal-int
+pkg syscall (darwin-386), const VEOL ideal-int
+pkg syscall (darwin-386), const VEOL2 ideal-int
+pkg syscall (darwin-386), const VERASE ideal-int
+pkg syscall (darwin-386), const VINTR ideal-int
+pkg syscall (darwin-386), const VKILL ideal-int
+pkg syscall (darwin-386), const VLNEXT ideal-int
+pkg syscall (darwin-386), const VMIN ideal-int
+pkg syscall (darwin-386), const VQUIT ideal-int
+pkg syscall (darwin-386), const VREPRINT ideal-int
+pkg syscall (darwin-386), const VSTART ideal-int
+pkg syscall (darwin-386), const VSTATUS ideal-int
+pkg syscall (darwin-386), const VSTOP ideal-int
+pkg syscall (darwin-386), const VSUSP ideal-int
+pkg syscall (darwin-386), const VT0 ideal-int
+pkg syscall (darwin-386), const VT1 ideal-int
+pkg syscall (darwin-386), const VTDLY ideal-int
+pkg syscall (darwin-386), const VTIME ideal-int
+pkg syscall (darwin-386), const VWERASE ideal-int
+pkg syscall (darwin-386), type Termios struct
+pkg syscall (darwin-386), type Termios struct, Cc [20]uint8
+pkg syscall (darwin-386), type Termios struct, Cflag uint32
+pkg syscall (darwin-386), type Termios struct, Iflag uint32
+pkg syscall (darwin-386), type Termios struct, Ispeed uint32
+pkg syscall (darwin-386), type Termios struct, Lflag uint32
+pkg syscall (darwin-386), type Termios struct, Oflag uint32
+pkg syscall (darwin-386), type Termios struct, Ospeed uint32
+pkg syscall (darwin-386-cgo), const B0 ideal-int
+pkg syscall (darwin-386-cgo), const B110 ideal-int
+pkg syscall (darwin-386-cgo), const B115200 ideal-int
+pkg syscall (darwin-386-cgo), const B1200 ideal-int
+pkg syscall (darwin-386-cgo), const B134 ideal-int
+pkg syscall (darwin-386-cgo), const B14400 ideal-int
+pkg syscall (darwin-386-cgo), const B150 ideal-int
+pkg syscall (darwin-386-cgo), const B1800 ideal-int
+pkg syscall (darwin-386-cgo), const B19200 ideal-int
+pkg syscall (darwin-386-cgo), const B200 ideal-int
+pkg syscall (darwin-386-cgo), const B230400 ideal-int
+pkg syscall (darwin-386-cgo), const B2400 ideal-int
+pkg syscall (darwin-386-cgo), const B28800 ideal-int
+pkg syscall (darwin-386-cgo), const B300 ideal-int
+pkg syscall (darwin-386-cgo), const B38400 ideal-int
+pkg syscall (darwin-386-cgo), const B4800 ideal-int
+pkg syscall (darwin-386-cgo), const B50 ideal-int
+pkg syscall (darwin-386-cgo), const B57600 ideal-int
+pkg syscall (darwin-386-cgo), const B600 ideal-int
+pkg syscall (darwin-386-cgo), const B7200 ideal-int
+pkg syscall (darwin-386-cgo), const B75 ideal-int
+pkg syscall (darwin-386-cgo), const B76800 ideal-int
+pkg syscall (darwin-386-cgo), const B9600 ideal-int
+pkg syscall (darwin-386-cgo), const BRKINT ideal-int
+pkg syscall (darwin-386-cgo), const CFLUSH ideal-int
+pkg syscall (darwin-386-cgo), const CLOCAL ideal-int
+pkg syscall (darwin-386-cgo), const CREAD ideal-int
+pkg syscall (darwin-386-cgo), const CS5 ideal-int
+pkg syscall (darwin-386-cgo), const CS6 ideal-int
+pkg syscall (darwin-386-cgo), const CS7 ideal-int
+pkg syscall (darwin-386-cgo), const CS8 ideal-int
+pkg syscall (darwin-386-cgo), const CSIZE ideal-int
+pkg syscall (darwin-386-cgo), const CSTART ideal-int
+pkg syscall (darwin-386-cgo), const CSTATUS ideal-int
+pkg syscall (darwin-386-cgo), const CSTOP ideal-int
+pkg syscall (darwin-386-cgo), const CSTOPB ideal-int
+pkg syscall (darwin-386-cgo), const CSUSP ideal-int
+pkg syscall (darwin-386-cgo), const FLUSHO ideal-int
+pkg syscall (darwin-386-cgo), const HUPCL ideal-int
+pkg syscall (darwin-386-cgo), const ICANON ideal-int
+pkg syscall (darwin-386-cgo), const ICRNL ideal-int
+pkg syscall (darwin-386-cgo), const IEXTEN ideal-int
+pkg syscall (darwin-386-cgo), const IGNBRK ideal-int
+pkg syscall (darwin-386-cgo), const IGNCR ideal-int
+pkg syscall (darwin-386-cgo), const IGNPAR ideal-int
+pkg syscall (darwin-386-cgo), const IMAXBEL ideal-int
+pkg syscall (darwin-386-cgo), const INLCR ideal-int
+pkg syscall (darwin-386-cgo), const INPCK ideal-int
+pkg syscall (darwin-386-cgo), const ISIG ideal-int
+pkg syscall (darwin-386-cgo), const ISTRIP ideal-int
+pkg syscall (darwin-386-cgo), const IUTF8 ideal-int
+pkg syscall (darwin-386-cgo), const IXANY ideal-int
+pkg syscall (darwin-386-cgo), const IXOFF ideal-int
+pkg syscall (darwin-386-cgo), const IXON ideal-int
+pkg syscall (darwin-386-cgo), const NOFLSH ideal-int
+pkg syscall (darwin-386-cgo), const OCRNL ideal-int
+pkg syscall (darwin-386-cgo), const OFDEL ideal-int
+pkg syscall (darwin-386-cgo), const OFILL ideal-int
+pkg syscall (darwin-386-cgo), const ONLCR ideal-int
+pkg syscall (darwin-386-cgo), const ONLRET ideal-int
+pkg syscall (darwin-386-cgo), const ONOCR ideal-int
+pkg syscall (darwin-386-cgo), const ONOEOT ideal-int
+pkg syscall (darwin-386-cgo), const OPOST ideal-int
+pkg syscall (darwin-386-cgo), const PARENB ideal-int
+pkg syscall (darwin-386-cgo), const PARMRK ideal-int
+pkg syscall (darwin-386-cgo), const PARODD ideal-int
+pkg syscall (darwin-386-cgo), const PENDIN ideal-int
+pkg syscall (darwin-386-cgo), const TCIFLUSH ideal-int
+pkg syscall (darwin-386-cgo), const TCIOFLUSH ideal-int
+pkg syscall (darwin-386-cgo), const TCOFLUSH ideal-int
+pkg syscall (darwin-386-cgo), const TCSAFLUSH ideal-int
+pkg syscall (darwin-386-cgo), const TOSTOP ideal-int
+pkg syscall (darwin-386-cgo), const VDISCARD ideal-int
+pkg syscall (darwin-386-cgo), const VDSUSP ideal-int
+pkg syscall (darwin-386-cgo), const VEOF ideal-int
+pkg syscall (darwin-386-cgo), const VEOL ideal-int
+pkg syscall (darwin-386-cgo), const VEOL2 ideal-int
+pkg syscall (darwin-386-cgo), const VERASE ideal-int
+pkg syscall (darwin-386-cgo), const VINTR ideal-int
+pkg syscall (darwin-386-cgo), const VKILL ideal-int
+pkg syscall (darwin-386-cgo), const VLNEXT ideal-int
+pkg syscall (darwin-386-cgo), const VMIN ideal-int
+pkg syscall (darwin-386-cgo), const VQUIT ideal-int
+pkg syscall (darwin-386-cgo), const VREPRINT ideal-int
+pkg syscall (darwin-386-cgo), const VSTART ideal-int
+pkg syscall (darwin-386-cgo), const VSTATUS ideal-int
+pkg syscall (darwin-386-cgo), const VSTOP ideal-int
+pkg syscall (darwin-386-cgo), const VSUSP ideal-int
+pkg syscall (darwin-386-cgo), const VT0 ideal-int
+pkg syscall (darwin-386-cgo), const VT1 ideal-int
+pkg syscall (darwin-386-cgo), const VTDLY ideal-int
+pkg syscall (darwin-386-cgo), const VTIME ideal-int
+pkg syscall (darwin-386-cgo), const VWERASE ideal-int
+pkg syscall (darwin-386-cgo), type Termios struct
+pkg syscall (darwin-386-cgo), type Termios struct, Cc [20]uint8
+pkg syscall (darwin-386-cgo), type Termios struct, Cflag uint32
+pkg syscall (darwin-386-cgo), type Termios struct, Iflag uint32
+pkg syscall (darwin-386-cgo), type Termios struct, Ispeed uint32
+pkg syscall (darwin-386-cgo), type Termios struct, Lflag uint32
+pkg syscall (darwin-386-cgo), type Termios struct, Oflag uint32
+pkg syscall (darwin-386-cgo), type Termios struct, Ospeed uint32
+pkg syscall (darwin-amd64), const B0 ideal-int
+pkg syscall (darwin-amd64), const B110 ideal-int
+pkg syscall (darwin-amd64), const B115200 ideal-int
+pkg syscall (darwin-amd64), const B1200 ideal-int
+pkg syscall (darwin-amd64), const B134 ideal-int
+pkg syscall (darwin-amd64), const B14400 ideal-int
+pkg syscall (darwin-amd64), const B150 ideal-int
+pkg syscall (darwin-amd64), const B1800 ideal-int
+pkg syscall (darwin-amd64), const B19200 ideal-int
+pkg syscall (darwin-amd64), const B200 ideal-int
+pkg syscall (darwin-amd64), const B230400 ideal-int
+pkg syscall (darwin-amd64), const B2400 ideal-int
+pkg syscall (darwin-amd64), const B28800 ideal-int
+pkg syscall (darwin-amd64), const B300 ideal-int
+pkg syscall (darwin-amd64), const B38400 ideal-int
+pkg syscall (darwin-amd64), const B4800 ideal-int
+pkg syscall (darwin-amd64), const B50 ideal-int
+pkg syscall (darwin-amd64), const B57600 ideal-int
+pkg syscall (darwin-amd64), const B600 ideal-int
+pkg syscall (darwin-amd64), const B7200 ideal-int
+pkg syscall (darwin-amd64), const B75 ideal-int
+pkg syscall (darwin-amd64), const B76800 ideal-int
+pkg syscall (darwin-amd64), const B9600 ideal-int
+pkg syscall (darwin-amd64), const BRKINT ideal-int
+pkg syscall (darwin-amd64), const CFLUSH ideal-int
+pkg syscall (darwin-amd64), const CLOCAL ideal-int
+pkg syscall (darwin-amd64), const CREAD ideal-int
+pkg syscall (darwin-amd64), const CS5 ideal-int
+pkg syscall (darwin-amd64), const CS6 ideal-int
+pkg syscall (darwin-amd64), const CS7 ideal-int
+pkg syscall (darwin-amd64), const CS8 ideal-int
+pkg syscall (darwin-amd64), const CSIZE ideal-int
+pkg syscall (darwin-amd64), const CSTART ideal-int
+pkg syscall (darwin-amd64), const CSTATUS ideal-int
+pkg syscall (darwin-amd64), const CSTOP ideal-int
+pkg syscall (darwin-amd64), const CSTOPB ideal-int
+pkg syscall (darwin-amd64), const CSUSP ideal-int
+pkg syscall (darwin-amd64), const FLUSHO ideal-int
+pkg syscall (darwin-amd64), const HUPCL ideal-int
+pkg syscall (darwin-amd64), const ICANON ideal-int
+pkg syscall (darwin-amd64), const ICRNL ideal-int
+pkg syscall (darwin-amd64), const IEXTEN ideal-int
+pkg syscall (darwin-amd64), const IGNBRK ideal-int
+pkg syscall (darwin-amd64), const IGNCR ideal-int
+pkg syscall (darwin-amd64), const IGNPAR ideal-int
+pkg syscall (darwin-amd64), const IMAXBEL ideal-int
+pkg syscall (darwin-amd64), const INLCR ideal-int
+pkg syscall (darwin-amd64), const INPCK ideal-int
+pkg syscall (darwin-amd64), const ISIG ideal-int
+pkg syscall (darwin-amd64), const ISTRIP ideal-int
+pkg syscall (darwin-amd64), const IUTF8 ideal-int
+pkg syscall (darwin-amd64), const IXANY ideal-int
+pkg syscall (darwin-amd64), const IXOFF ideal-int
+pkg syscall (darwin-amd64), const IXON ideal-int
+pkg syscall (darwin-amd64), const NOFLSH ideal-int
+pkg syscall (darwin-amd64), const OCRNL ideal-int
+pkg syscall (darwin-amd64), const OFDEL ideal-int
+pkg syscall (darwin-amd64), const OFILL ideal-int
+pkg syscall (darwin-amd64), const ONLCR ideal-int
+pkg syscall (darwin-amd64), const ONLRET ideal-int
+pkg syscall (darwin-amd64), const ONOCR ideal-int
+pkg syscall (darwin-amd64), const ONOEOT ideal-int
+pkg syscall (darwin-amd64), const OPOST ideal-int
+pkg syscall (darwin-amd64), const PARENB ideal-int
+pkg syscall (darwin-amd64), const PARMRK ideal-int
+pkg syscall (darwin-amd64), const PARODD ideal-int
+pkg syscall (darwin-amd64), const PENDIN ideal-int
+pkg syscall (darwin-amd64), const TCIFLUSH ideal-int
+pkg syscall (darwin-amd64), const TCIOFLUSH ideal-int
+pkg syscall (darwin-amd64), const TCOFLUSH ideal-int
+pkg syscall (darwin-amd64), const TCSAFLUSH ideal-int
+pkg syscall (darwin-amd64), const TOSTOP ideal-int
+pkg syscall (darwin-amd64), const VDISCARD ideal-int
+pkg syscall (darwin-amd64), const VDSUSP ideal-int
+pkg syscall (darwin-amd64), const VEOF ideal-int
+pkg syscall (darwin-amd64), const VEOL ideal-int
+pkg syscall (darwin-amd64), const VEOL2 ideal-int
+pkg syscall (darwin-amd64), const VERASE ideal-int
+pkg syscall (darwin-amd64), const VINTR ideal-int
+pkg syscall (darwin-amd64), const VKILL ideal-int
+pkg syscall (darwin-amd64), const VLNEXT ideal-int
+pkg syscall (darwin-amd64), const VMIN ideal-int
+pkg syscall (darwin-amd64), const VQUIT ideal-int
+pkg syscall (darwin-amd64), const VREPRINT ideal-int
+pkg syscall (darwin-amd64), const VSTART ideal-int
+pkg syscall (darwin-amd64), const VSTATUS ideal-int
+pkg syscall (darwin-amd64), const VSTOP ideal-int
+pkg syscall (darwin-amd64), const VSUSP ideal-int
+pkg syscall (darwin-amd64), const VT0 ideal-int
+pkg syscall (darwin-amd64), const VT1 ideal-int
+pkg syscall (darwin-amd64), const VTDLY ideal-int
+pkg syscall (darwin-amd64), const VTIME ideal-int
+pkg syscall (darwin-amd64), const VWERASE ideal-int
+pkg syscall (darwin-amd64), type Termios struct
+pkg syscall (darwin-amd64), type Termios struct, Cc [20]uint8
+pkg syscall (darwin-amd64), type Termios struct, Cflag uint64
+pkg syscall (darwin-amd64), type Termios struct, Iflag uint64
+pkg syscall (darwin-amd64), type Termios struct, Ispeed uint64
+pkg syscall (darwin-amd64), type Termios struct, Lflag uint64
+pkg syscall (darwin-amd64), type Termios struct, Oflag uint64
+pkg syscall (darwin-amd64), type Termios struct, Ospeed uint64
+pkg syscall (darwin-amd64), type Termios struct, Pad_cgo_0 [4]byte
+pkg syscall (darwin-amd64-cgo), const B0 ideal-int
+pkg syscall (darwin-amd64-cgo), const B110 ideal-int
+pkg syscall (darwin-amd64-cgo), const B115200 ideal-int
+pkg syscall (darwin-amd64-cgo), const B1200 ideal-int
+pkg syscall (darwin-amd64-cgo), const B134 ideal-int
+pkg syscall (darwin-amd64-cgo), const B14400 ideal-int
+pkg syscall (darwin-amd64-cgo), const B150 ideal-int
+pkg syscall (darwin-amd64-cgo), const B1800 ideal-int
+pkg syscall (darwin-amd64-cgo), const B19200 ideal-int
+pkg syscall (darwin-amd64-cgo), const B200 ideal-int
+pkg syscall (darwin-amd64-cgo), const B230400 ideal-int
+pkg syscall (darwin-amd64-cgo), const B2400 ideal-int
+pkg syscall (darwin-amd64-cgo), const B28800 ideal-int
+pkg syscall (darwin-amd64-cgo), const B300 ideal-int
+pkg syscall (darwin-amd64-cgo), const B38400 ideal-int
+pkg syscall (darwin-amd64-cgo), const B4800 ideal-int
+pkg syscall (darwin-amd64-cgo), const B50 ideal-int
+pkg syscall (darwin-amd64-cgo), const B57600 ideal-int
+pkg syscall (darwin-amd64-cgo), const B600 ideal-int
+pkg syscall (darwin-amd64-cgo), const B7200 ideal-int
+pkg syscall (darwin-amd64-cgo), const B75 ideal-int
+pkg syscall (darwin-amd64-cgo), const B76800 ideal-int
+pkg syscall (darwin-amd64-cgo), const B9600 ideal-int
+pkg syscall (darwin-amd64-cgo), const BRKINT ideal-int
+pkg syscall (darwin-amd64-cgo), const CFLUSH ideal-int
+pkg syscall (darwin-amd64-cgo), const CLOCAL ideal-int
+pkg syscall (darwin-amd64-cgo), const CREAD ideal-int
+pkg syscall (darwin-amd64-cgo), const CS5 ideal-int
+pkg syscall (darwin-amd64-cgo), const CS6 ideal-int
+pkg syscall (darwin-amd64-cgo), const CS7 ideal-int
+pkg syscall (darwin-amd64-cgo), const CS8 ideal-int
+pkg syscall (darwin-amd64-cgo), const CSIZE ideal-int
+pkg syscall (darwin-amd64-cgo), const CSTART ideal-int
+pkg syscall (darwin-amd64-cgo), const CSTATUS ideal-int
+pkg syscall (darwin-amd64-cgo), const CSTOP ideal-int
+pkg syscall (darwin-amd64-cgo), const CSTOPB ideal-int
+pkg syscall (darwin-amd64-cgo), const CSUSP ideal-int
+pkg syscall (darwin-amd64-cgo), const FLUSHO ideal-int
+pkg syscall (darwin-amd64-cgo), const HUPCL ideal-int
+pkg syscall (darwin-amd64-cgo), const ICANON ideal-int
+pkg syscall (darwin-amd64-cgo), const ICRNL ideal-int
+pkg syscall (darwin-amd64-cgo), const IEXTEN ideal-int
+pkg syscall (darwin-amd64-cgo), const IGNBRK ideal-int
+pkg syscall (darwin-amd64-cgo), const IGNCR ideal-int
+pkg syscall (darwin-amd64-cgo), const IGNPAR ideal-int
+pkg syscall (darwin-amd64-cgo), const IMAXBEL ideal-int
+pkg syscall (darwin-amd64-cgo), const INLCR ideal-int
+pkg syscall (darwin-amd64-cgo), const INPCK ideal-int
+pkg syscall (darwin-amd64-cgo), const ISIG ideal-int
+pkg syscall (darwin-amd64-cgo), const ISTRIP ideal-int
+pkg syscall (darwin-amd64-cgo), const IUTF8 ideal-int
+pkg syscall (darwin-amd64-cgo), const IXANY ideal-int
+pkg syscall (darwin-amd64-cgo), const IXOFF ideal-int
+pkg syscall (darwin-amd64-cgo), const IXON ideal-int
+pkg syscall (darwin-amd64-cgo), const NOFLSH ideal-int
+pkg syscall (darwin-amd64-cgo), const OCRNL ideal-int
+pkg syscall (darwin-amd64-cgo), const OFDEL ideal-int
+pkg syscall (darwin-amd64-cgo), const OFILL ideal-int
+pkg syscall (darwin-amd64-cgo), const ONLCR ideal-int
+pkg syscall (darwin-amd64-cgo), const ONLRET ideal-int
+pkg syscall (darwin-amd64-cgo), const ONOCR ideal-int
+pkg syscall (darwin-amd64-cgo), const ONOEOT ideal-int
+pkg syscall (darwin-amd64-cgo), const OPOST ideal-int
+pkg syscall (darwin-amd64-cgo), const PARENB ideal-int
+pkg syscall (darwin-amd64-cgo), const PARMRK ideal-int
+pkg syscall (darwin-amd64-cgo), const PARODD ideal-int
+pkg syscall (darwin-amd64-cgo), const PENDIN ideal-int
+pkg syscall (darwin-amd64-cgo), const TCIFLUSH ideal-int
+pkg syscall (darwin-amd64-cgo), const TCIOFLUSH ideal-int
+pkg syscall (darwin-amd64-cgo), const TCOFLUSH ideal-int
+pkg syscall (darwin-amd64-cgo), const TCSAFLUSH ideal-int
+pkg syscall (darwin-amd64-cgo), const TOSTOP ideal-int
+pkg syscall (darwin-amd64-cgo), const VDISCARD ideal-int
+pkg syscall (darwin-amd64-cgo), const VDSUSP ideal-int
+pkg syscall (darwin-amd64-cgo), const VEOF ideal-int
+pkg syscall (darwin-amd64-cgo), const VEOL ideal-int
+pkg syscall (darwin-amd64-cgo), const VEOL2 ideal-int
+pkg syscall (darwin-amd64-cgo), const VERASE ideal-int
+pkg syscall (darwin-amd64-cgo), const VINTR ideal-int
+pkg syscall (darwin-amd64-cgo), const VKILL ideal-int
+pkg syscall (darwin-amd64-cgo), const VLNEXT ideal-int
+pkg syscall (darwin-amd64-cgo), const VMIN ideal-int
+pkg syscall (darwin-amd64-cgo), const VQUIT ideal-int
+pkg syscall (darwin-amd64-cgo), const VREPRINT ideal-int
+pkg syscall (darwin-amd64-cgo), const VSTART ideal-int
+pkg syscall (darwin-amd64-cgo), const VSTATUS ideal-int
+pkg syscall (darwin-amd64-cgo), const VSTOP ideal-int
+pkg syscall (darwin-amd64-cgo), const VSUSP ideal-int
+pkg syscall (darwin-amd64-cgo), const VT0 ideal-int
+pkg syscall (darwin-amd64-cgo), const VT1 ideal-int
+pkg syscall (darwin-amd64-cgo), const VTDLY ideal-int
+pkg syscall (darwin-amd64-cgo), const VTIME ideal-int
+pkg syscall (darwin-amd64-cgo), const VWERASE ideal-int
+pkg syscall (darwin-amd64-cgo), type Termios struct
+pkg syscall (darwin-amd64-cgo), type Termios struct, Cc [20]uint8
+pkg syscall (darwin-amd64-cgo), type Termios struct, Cflag uint64
+pkg syscall (darwin-amd64-cgo), type Termios struct, Iflag uint64
+pkg syscall (darwin-amd64-cgo), type Termios struct, Ispeed uint64
+pkg syscall (darwin-amd64-cgo), type Termios struct, Lflag uint64
+pkg syscall (darwin-amd64-cgo), type Termios struct, Oflag uint64
+pkg syscall (darwin-amd64-cgo), type Termios struct, Ospeed uint64
+pkg syscall (darwin-amd64-cgo), type Termios struct, Pad_cgo_0 [4]byte
+pkg syscall (windows-386), const CREATE_NEW_PROCESS_GROUP ideal-int
+pkg syscall (windows-386), const CTRL_BREAK_EVENT ideal-int
+pkg syscall (windows-386), const CTRL_C_EVENT ideal-int
+pkg syscall (windows-386), func GetCurrentProcessId() uint32
+pkg syscall (windows-386), type SysProcAttr struct, CreationFlags uint32
+pkg syscall (windows-amd64), const CREATE_NEW_PROCESS_GROUP ideal-int
+pkg syscall (windows-amd64), const CTRL_BREAK_EVENT ideal-int
+pkg syscall (windows-amd64), const CTRL_C_EVENT ideal-int
+pkg syscall (windows-amd64), func GetCurrentProcessId() uint32
+pkg syscall (windows-amd64), type SysProcAttr struct, CreationFlags uint32

src/cmd/api/goapi.go

@@ -35,8 +35,12 @@ import (
 
 // Flags
 var (
+	// TODO(bradfitz): once Go 1.1 comes out, allow the -c flag to take a comma-separated
+	// list of files, rather than just one.
 	checkFile = flag.String("c", "", "optional filename to check API against")
-	verbose   = flag.Bool("v", false, "Verbose debugging")
+	allowNew  = flag.Bool("allow_new", true, "allow API additions")
+	nextFile  = flag.String("next", "", "optional filename of tentative upcoming API features for the next release. This file can be lazily maintained. It only affects the delta warnings from the -c file printed on success.")
+	verbose   = flag.Bool("v", false, "verbose debugging")
 )
 
 var contexts = []*build.Context{
@@ -123,45 +127,82 @@ func main() {
 	}
 	sort.Strings(features)
 
+	fail := false
+	defer func() {
+		if fail {
+			os.Exit(1)
+		}
+	}()
+
 	bw := bufio.NewWriter(os.Stdout)
 	defer bw.Flush()
 
-	if *checkFile != "" {
-		bs, err := ioutil.ReadFile(*checkFile)
-		if err != nil {
-			log.Fatalf("Error reading file %s: %v", *checkFile, err)
-		}
-		v1 := strings.Split(strings.TrimSpace(string(bs)), "\n")
-		sort.Strings(v1)
-		v2 := features
-		take := func(sl *[]string) string {
-			s := (*sl)[0]
-			*sl = (*sl)[1:]
-			return s
-		}
-		changes := false
-		for len(v1) > 0 || len(v2) > 0 {
-			switch {
-			case len(v2) == 0 || v1[0] < v2[0]:
-				fmt.Fprintf(bw, "-%s\n", take(&v1))
-				changes = true
-			case len(v1) == 0 || v1[0] > v2[0]:
-				fmt.Fprintf(bw, "+%s\n", take(&v2))
-				// we allow API additions now
-			default:
-				take(&v1)
-				take(&v2)
-			}
-		}
-		if changes {
-			bw.Flush()
-			os.Exit(1)
-		}
-	} else {
+	if *checkFile == "" {
 		for _, f := range features {
 			fmt.Fprintf(bw, "%s\n", f)
 		}
+		return
+	}
+
+	var required []string
+	for _, filename := range []string{*checkFile} {
+		required = append(required, fileFeatures(filename)...)
+	}
+	sort.Strings(required)
+
+	var optional = make(map[string]bool) // feature => true
+	if *nextFile != "" {
+		for _, feature := range fileFeatures(*nextFile) {
+			optional[feature] = true
+		}
+	}
+
+	take := func(sl *[]string) string {
+		s := (*sl)[0]
+		*sl = (*sl)[1:]
+		return s
+	}
+
+	for len(required) > 0 || len(features) > 0 {
+		switch {
+		case len(features) == 0 || required[0] < features[0]:
+			fmt.Fprintf(bw, "-%s\n", take(&required))
+			fail = true // broke compatibility
+		case len(required) == 0 || required[0] > features[0]:
+			newFeature := take(&features)
+			if optional[newFeature] {
+				// Known added feature to the upcoming release.
+				// Delete it from the map so we can detect any upcoming features
+				// which were never seen.  (so we can clean up the nextFile)
+				delete(optional, newFeature)
+			} else {
+				fmt.Fprintf(bw, "+%s\n", newFeature)
+				if !*allowNew {
+					fail = true // we're in lock-down mode for next release
+				}
+			}
+		default:
+			take(&required)
+			take(&features)
+		}
+	}
+
+	var missing []string
+	for feature := range optional {
+		missing = append(missing, feature)
+	}
+	sort.Strings(missing)
+	for _, feature := range missing {
+		fmt.Fprintf(bw, "(in next file, but not in API) -%s\n", feature)
+	}
+}
+
+func fileFeatures(filename string) []string {
+	bs, err := ioutil.ReadFile(filename)
+	if err != nil {
+		log.Fatalf("Error reading file %s: %v", filename, err)
 	}
+	return strings.Split(strings.TrimSpace(string(bs)), "\n")
 }
 
 // pkgSymbol represents a symbol in a package

src/run.bash

@@ -106,7 +106,7 @@ time go run run.go
 
 echo
 echo '# Checking API compatibility.'
-go tool api -c $GOROOT/api/go1.txt
+go tool api -c $GOROOT/api/go1.txt -next $GOROOT/api/next.txt
 
 echo
 echo ALL TESTS PASSED

src/run.bat

@@ -68,7 +68,7 @@ echo.
 if %FAIL%==1 goto fail
 
 echo # Checking API compatibility.
-go tool api -c ..\api\go1.txt
+go tool api -c ..\api\go1.txt -next ..\api\next.txt
 if errorlevel 1 goto fail
 echo.