void get_arc_coordinates();
+void serial_echopair(const PROGMEM char *s, float v)
+ { serialprintPGM(s); SERIAL_ECHO(v); }
+void serial_echopair(const PROGMEM char *s, double v)
+ { serialprintPGM(s); SERIAL_ECHO(v); }
+void serial_echopair(const PROGMEM char *s, unsigned long v)
+ { serialprintPGM(s); SERIAL_ECHO(v); }
+
extern "C"{
extern unsigned int __bss_end;
extern unsigned int __heap_start;