Fix some warnings with examples.

examples/data_source_chaining.c

@@ -49,6 +49,8 @@ ma_decoder* g_pDecoders;
 
 static ma_data_source* next_callback_tail(ma_data_source* pDataSource)
 {
+    (void)pDataSource;  /* Unused. */
+
     if (g_decoderCount > 0) {   /* <-- We check for this in main() so should never happen. */
         return NULL;
     }

examples/hilo_interop.c

@@ -28,6 +28,8 @@ void capture_data_callback(ma_device* pDevice, void* pFramesOut, const void* pFr
     ma_result result;
     ma_uint32 framesWritten;
 
+    (void)pFramesOut;
+
     /* We need to write to the ring buffer. Need to do this in a loop. */
     framesWritten = 0;
     while (framesWritten < frameCount) {

examples/resource_manager_advanced.c

@@ -266,7 +266,7 @@ int main(int argc, char** argv)
     ma_thread_create(&jobThread, ma_thread_priority_default, 0, custom_job_thread, &resourceManager, NULL);
 
     /* Create each data source from the resource manager. Note that the caller is the owner. */
-    for (iFile = 0; iFile < ma_countof(g_dataSources) && iFile < argc-1; iFile += 1) {
+    for (iFile = 0; iFile < (int)ma_countof(g_dataSources) && iFile < argc-1; iFile += 1) {
         result = ma_resource_manager_data_source_init(
             &resourceManager,
             argv[iFile+1],

examples/simple_mixing.c

@@ -29,7 +29,7 @@ ma_bool32*  g_pDecodersAtEnd;
 
 ma_event g_stopEvent; /* <-- Signaled by the audio thread, waited on by the main thread. */
 
-ma_bool32 are_all_decoders_at_end()
+ma_bool32 are_all_decoders_at_end(void)
 {
     ma_uint32 iDecoder;
     for (iDecoder = 0; iDecoder < g_decoderCount; ++iDecoder) {