fix build on SunOS (Sparc)

R=rsc
CC=codebot
http://codereview.appspot.com/882044

src/cmd/rio/key.c

@@ -6,6 +6,7 @@
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 #include <X11/Xatom.h>
+#include <X11/keysym.h>
 #include <X11/extensions/shape.h>
 #include "dat.h"
 #include "fns.h"

src/mkhdr

@@ -12,6 +12,7 @@ OBJTYPE=`uname -m -p | sed '
 	s;.*ppc64.*;power;g;
 	s;.*ppc.*;power;g;
 	s;.*alpha.*;alpha;g;
+	s;.*sun4u.*;sun4u;g;
 '`
 
 BIN=$PLAN9/bin