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