Added #error to printf for examples that require Arduino

examples/pingpair_irq/printf.h

@@ -1,5 +1,5 @@
 /*
- Copyright (C) 2011 James Coliz, Jr. <maniacbug@ymail.com>
+ Copyright (C) 2011 J. Coliz <maniacbug@ymail.com>
  
  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License
@@ -16,6 +16,8 @@
 #ifndef __PRINTF_H__
 #define __PRINTF_H__
 
+#ifdef ARDUINO
+
 int serial_putc( char c, FILE * ) 
 {
   Serial.write( c );
@@ -28,4 +30,8 @@ void printf_begin(void)
   fdevopen( &serial_putc, 0 );
 }
 
+#else
+#error This example is only for use on Arduino.
+#endif // ARDUINO
+
 #endif // __PRINTF_H__