libobs: Fix warnings about implicit integer downcasts in macOS code

libobs/audio-monitoring/osx/coreaudio-output.c

@@ -43,7 +43,7 @@ static inline bool fill_buffer(struct audio_monitor *monitor)
 	circlebuf_pop_front(&monitor->new_data, buf->mAudioData,
 			    monitor->buffer_size);
 
-	buf->mAudioDataByteSize = monitor->buffer_size;
+	buf->mAudioDataByteSize = (UInt32)monitor->buffer_size;
 
 	stat = AudioQueueEnqueueBuffer(monitor->queue, buf, 0, NULL);
 	if (!success(stat, "AudioQueueEnqueueBuffer")) {
@@ -225,7 +225,7 @@ static bool audio_monitor_init(struct audio_monitor *monitor,
 
 	for (size_t i = 0; i < 3; i++) {
 		stat = AudioQueueAllocateBuffer(monitor->queue,
-						monitor->buffer_size,
+						(UInt32)monitor->buffer_size,
 						&monitor->buffers[i]);
 		if (!success(stat, "allocation of buffer")) {
 			return false;

libobs/obs-cocoa.m

@@ -322,7 +322,7 @@ obs_key_t obs_key_from_virtual_key(int code)
         return OBS_KEY_META;
     for (size_t i = 0; i < OBS_KEY_LAST_VALUE; i++) {
         if (virtual_keys[i] == code) {
-            return i;
+            return (obs_key_t) i;
         }
     }
     return OBS_KEY_NONE;

libobs/util/platform-cocoa.m

@@ -190,7 +190,7 @@ os_cpu_usage_info_t *os_cpu_usage_info_start(void)
         return NULL;
     }
 
-    info->core_count = sysconf(_SC_NPROCESSORS_ONLN);
+    info->core_count = (int) sysconf(_SC_NPROCESSORS_ONLN);
     return info;
 }