add weak implementation to fix compilation errors for other projects

Author: marcel-licence

src/ml_arp.cpp

@@ -288,3 +288,10 @@ uint32_t Arp_GetPos(void)
     return arp_pos;
 }
 
+/* please implement the following functions in your application */
+__attribute__((weak)) void Arp_Cb_NoteOn(uint8_t ch, uint8_t note, float vel) {};
+__attribute__((weak)) void Arp_Cb_NoteOff(uint8_t ch, uint8_t note) {};
+__attribute__((weak)) void Arp_Status_ValueChangedInt(const char *msg, int value) {};
+__attribute__((weak)) void Arp_Status_LogMessage(const char *msg) {};
+__attribute__((weak)) void Arp_Status_ValueChangedFloat(const char *msg, float value) {};
+__attribute__((weak)) void Arp_Cb_Step(uint8_t step) {};