Improves behavior of display subrs DSPBOUT and SHOWDISPLAY

DSPBOUT is called to output a single character to the "BCPL display",
which is the system text output rather than the bitmapped display.
Under maiko, this is mapped to "stdout". Interlisp-D uses CR as the EOL
character, but that is not appropriate for output to standard output
so CR is translated to LF here.  Standard output is buffered, but there
is no indication of when the output should be flushed, so flush on every
character, since this is a low frequency operation.

SHOWDISPLAY is called to switch between the "BCPL display" and the
bitmapped display.  The current display subsystems are not hooked up
to this subr, but this is a potential place to hook display size changes
in the future, so the code is updated to indicate the parameters passed
in and to set/reset the display initialization state variable.

Author: nbriggs

src/dspsubrs.c

@@ -40,7 +40,12 @@ extern int Mouse_Included;
  ****************************************************/
 
 void DSP_dspbout(LispPTR *args) /* args[0] :	charcode	*/
-{ putc((args[0] & 0xFFFF) & 0x7f, BCPLDISPLAY); }
+{
+  int charcode = (args[0] & 0x7F);
+  /* Interlisp-D uses CR as EOL which isn't useful here */
+  putc((charcode == '\r') ? '\n' : charcode, BCPLDISPLAY);
+  fflush(BCPLDISPLAY);
+}
 
 /****************************************************
  *
@@ -52,7 +57,16 @@ void DSP_dspbout(LispPTR *args) /* args[0] :	charcode	*/
 extern int DisplayInitialized;
 
 void DSP_showdisplay(LispPTR *args)
-{ DisplayInitialized = 1; }
+{
+  LispPTR base = args[0];   /* pointer to the display bitmap */
+  LispPTR rasterwidth = args[1];  /* should be a smallp */
+
+  if (base == NIL) {
+    DisplayInitialized = 0;
+  } else {
+    DisplayInitialized = 1;
+  }
+}
 
 /****************************************************
  *