* rl78/crt0.S: Initialize .saddr. Avoid using SEL.

* rl78/rl78-sim.ld: Add .saddr/.frodata section.
* rl78/rl78.ld: Likewise.
* rl78/rl78-sim.ld: Make room for virtual register banks.
* rl78/rl78.ld: Likewise.

* rl78/vregs.h: New.
* rl78-sys.h: Use it.
* rl78/swrite.S: New.
* rl78/Makefile.in: Build it.
* rl78/write.c: Use it.

libgloss/rl78/write.c

@@ -85,11 +85,17 @@ tputc (char c)
   SDR00 = c;
 }
 
+/* defaults to 0 unless open() is linked in */
+int _open_present;
+
 int
 _write(int fd, char *ptr, int len)
 {
   int rv = len;
 
+  if (_open_present && fd > 2)
+    return _SYS_write (fd, ptr, len);
+
   if (!initted)
     init_uart0 ();