Add basic termios to the rpi platform to allow echoing/newline translation to be controlled.

--HG--
branch : dtrg-videocore
rename : plat/rpi/include/unistd.h => plat/rpi/include/termios.h
rename : plat/rpi/libsys/write.c => plat/rpi/libsys/tcgetattr.c
rename : plat/rpi/libsys/write.c => plat/rpi/libsys/tcsetattr.c

plat/rpi/include/termios.h

@@ -0,0 +1,31 @@
+/*
+ * Raspberry Pi support library for the ACK
+ * © 2013 David Given
+ * This file is redistributable under the terms of the 3-clause BSD license.
+ * See the file 'Copying' in the root of the distribution for the full text.
+ */
+
+#ifndef _TERMIOS_H
+#define _TERMIOS_H
+
+typedef unsigned char tcflag_t;
+
+struct termios
+{
+    tcflag_t c_iflag;
+    tcflag_t c_oflag;
+    tcflag_t c_lflag;
+};
+
+#define ONLCR 1
+#define ECHO 2
+#define INLCR 4
+
+#define TCSANOW 0
+#define TCSADRAIN 1
+#define TCSAFLUSH 2
+
+extern int tcgetattr(int fd, struct termios* t);
+extern int tcsetattr(int fd, int actions, struct termios* t);
+
+#endif