Make use of doesclrscrafterexit().

samples/overlaydemo.c

@@ -10,7 +10,7 @@
 
 
 #include <stdio.h>
-#include <conio.h>
+#include <cc65.h>
 #ifndef __CBM__
 #include <fcntl.h>
 #include <unistd.h>
@@ -130,5 +130,7 @@ void main (void)
         foobar ();
     }
 
-    cgetc ();
+    if (doesclrscrafterexit ()) {
+        getchar ();
+    }
 }