Compilation fails on FreeBSD

[probonopd]

% go get github.com/fluepke/esptool
# github.com/fluepke/esptool/common/serial
go/src/github.com/fluepke/esptool/common/serial/ioctls.go:19:17: undefined: unix.TCSETS
go/src/github.com/fluepke/esptool/common/serial/serial_unix.go:95:17: undefined: unix.TCFLSH
go/src/github.com/fluepke/esptool/common/serial/serial_unix.go:119:12: undefined: unix.B500000
go/src/github.com/fluepke/esptool/common/serial/serial_unix.go:120:12: undefined: unix.B576000
go/src/github.com/fluepke/esptool/common/serial/serial_unix.go:122:12: undefined: unix.B1000000
go/src/github.com/fluepke/esptool/common/serial/serial_unix.go:123:12: undefined: unix.B1152000
go/src/github.com/fluepke/esptool/common/serial/serial_unix.go:124:12: undefined: unix.B1500000
go/src/github.com/fluepke/esptool/common/serial/serial_unix.go:125:12: undefined: unix.B2000000
go/src/github.com/fluepke/esptool/common/serial/serial_unix.go:126:12: undefined: unix.B2500000
go/src/github.com/fluepke/esptool/common/serial/serial_unix.go:127:12: undefined: unix.B3000000
go/src/github.com/fluepke/esptool/common/serial/serial_unix.go:127:12: too many errors

[Fluepke]

Yeah, I've not figured out, how to perform the required ioctls and set high baudrates with FreeBSD as I mostly run Linux.

Maybe you can improve my serial / termios implementation, that works cross platform?