test/{read_conf,run_filter}: convert to C++

src/filter/ReplayGainFilterPlugin.cxx

@@ -25,11 +25,11 @@
 #include "audio_format.h"
 #include "replay_gain_info.h"
 #include "replay_gain_config.h"
+#include "mixer_control.h"
 
 extern "C" {
 #include "pcm_buffer.h"
 #include "pcm_volume.h"
-#include "mixer_control.h"
 }
 
 #include <assert.h>

src/filter_plugin.h

@@ -74,6 +74,10 @@ struct filter_plugin {
 			      GError **error_r);
 };
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /**
  * Creates a new instance of the specified filter plugin.
  *
@@ -147,4 +151,8 @@ filter_filter(struct filter *filter, const void *src, size_t src_size,
 	      size_t *dest_size_r,
 	      GError **error_r);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif

src/mixer_control.h

@@ -33,6 +33,10 @@ struct mixer;
 struct mixer_plugin;
 struct config_param;
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct mixer *
 mixer_new(const struct mixer_plugin *plugin, void *ao,
 	  const struct config_param *param,
@@ -60,4 +64,8 @@ mixer_get_volume(struct mixer *mixer, GError **error_r);
 bool
 mixer_set_volume(struct mixer *mixer, unsigned volume, GError **error_r);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif