Fixed cross compilation on MIPS architecture (#10)

* Fixed termios portability issue.

* Cleaned up for cross compilation.

serial_posix.go

@@ -173,9 +173,9 @@ func newTermios(c *Config) (termios *syscall.Termios, err error) {
 	}
 	termios.Cflag |= flag
 	// Input baud.
-	termios.Ispeed = flag
+	cfSetIspeed(termios, flag)
 	// Output baud.
-	termios.Ospeed = flag
+	cfSetOspeed(termios, flag)
 	// Character size.
 	if c.DataBits == 0 {
 		flag = syscall.CS8

termios_bsd.go

@@ -0,0 +1,15 @@
+// +build freebsd openbsd netbsd
+
+package serial
+
+import (
+	"syscall"
+)
+
+func cfSetIspeed(termios *syscall.Termios, speed uint32) {
+	termios.Ispeed = speed
+}
+
+func cfSetOspeed(termios *syscall.Termios, speed uint32) {
+	termios.Ospeed = speed
+}

termios_darwin.go

@@ -0,0 +1,13 @@
+package serial
+
+import (
+	"syscall"
+)
+
+func cfSetIspeed(termios *syscall.Termios, speed uint64) {
+	termios.Ispeed = speed
+}
+
+func cfSetOspeed(termios *syscall.Termios, speed uint64) {
+	termios.Ospeed = speed
+}

termios_linux.go

@@ -0,0 +1,15 @@
+// +build !mips,!mipsle,!mips64,!mips64le
+
+package serial
+
+import (
+	"syscall"
+)
+
+func cfSetIspeed(termios *syscall.Termios, speed uint32) {
+	termios.Ispeed = speed
+}
+
+func cfSetOspeed(termios *syscall.Termios, speed uint32) {
+	termios.Ospeed = speed
+}

termios_mipsx.go

@@ -0,0 +1,16 @@
+// +build linux
+// +build mips mipsle mips64 mips64le
+
+package serial
+
+import (
+	"syscall"
+)
+
+func cfSetIspeed(termios *syscall.Termios, speed uint32) {
+	// MIPS has no Ispeed field in termios.
+}
+
+func cfSetOspeed(termios *syscall.Termios, speed uint32) {
+	// MIPS has no Ospeed field in termios.
+}