small fixes (#109)

components/dsp_processor/include/dsp_processor.h

@@ -1,6 +1,10 @@
 #ifndef _DSP_PROCESSOR_H_
 #define _DSP_PROCESSOR_H_
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "esp_err.h"
 
 typedef enum dspFlows {
@@ -64,4 +68,8 @@ int dsp_processor_worker(char *audio, size_t chunk_size, uint32_t samplerate);
 esp_err_t dsp_processor_update_filter_params(filterParams_t *params);
 void dsp_processor_set_volome(double volume);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* _DSP_PROCESSOR_H_  */