sparse: replace 0 (integer) usage with NULL where appropriate

src/audioOutputs/audioOutput_alsa.c

@@ -208,7 +208,7 @@ static int alsa_openDevice(AudioOutput * audioOutput)
 	audioFormat->channels = channels;
 
 	err = snd_pcm_hw_params_set_rate_near(ad->pcmHandle, hwparams, 
-			&sampleRate, 0);
+			&sampleRate, NULL);
 	if(err < 0 || sampleRate == 0) {
 		ERROR("Alsa device \"%s\" does not support %i Hz audio\n",
 				ad->device, (int)audioFormat->sampleRate);
@@ -218,14 +218,14 @@ static int alsa_openDevice(AudioOutput * audioOutput)
 
 	cmd = "snd_pcm_hw_params_set_buffer_time_near";
 	err = snd_pcm_hw_params_set_buffer_time_near(ad->pcmHandle, hwparams,
-			&ad->buffer_time, 0);
+			&ad->buffer_time, NULL);
 	if(err < 0) goto error;
 
 	if (!ad->period_time && sampleRate > 0)
 		ad->period_time = 1000000 * MPD_ALSA_SAMPLE_XFER / sampleRate;
 	cmd = "snd_pcm_hw_params_set_period_time_near";
 	err = snd_pcm_hw_params_set_period_time_near(ad->pcmHandle, hwparams,
-			&ad->period_time, 0);
+			&ad->period_time, NULL);
 	if(err < 0) goto error;
 
 	cmd = "snd_pcm_hw_params";
@@ -237,7 +237,8 @@ static int alsa_openDevice(AudioOutput * audioOutput)
 	if(err < 0) goto error;
 
 	cmd = "snd_pcm_hw_params_get_period_size";
-	err = snd_pcm_hw_params_get_period_size(hwparams, &alsa_period_size, 0);
+	err = snd_pcm_hw_params_get_period_size(hwparams, &alsa_period_size,
+	                                        NULL);
 	if(err < 0) goto error;
 
 	ad->canPause = snd_pcm_hw_params_can_pause(hwparams);

src/playerData.c

@@ -99,7 +99,7 @@ void initPlayerData(void) {
 		ERROR("problems shmat'ing\n");
 		exit(EXIT_FAILURE);
 	}
-	if (shmctl(shmid, IPC_RMID, 0)<0) {
+	if (shmctl(shmid, IPC_RMID, NULL)<0) {
 		ERROR("problems shmctl'ing\n");
 		exit(EXIT_FAILURE);
 	}
@@ -115,7 +115,7 @@ void initPlayerData(void) {
 		ERROR("problems shmat'ing\n");
 		exit(EXIT_FAILURE);
 	}
-	if (shmctl(shmid, IPC_RMID, 0)<0) {
+	if (shmctl(shmid, IPC_RMID, NULL)<0) {
 		ERROR("problems shmctl'ing\n");
 		exit(EXIT_FAILURE);
 	}

src/signal_check.c

@@ -20,6 +20,7 @@
 #include "signal_check.h"
 
 #include <errno.h>
+#include <stddef.h>
 
 volatile sig_atomic_t __caught_signals[NSIG];
 
@@ -33,7 +34,7 @@ static void __set_signal_handler(int sig, void (* handler)(int))
         struct sigaction act;
         act.sa_flags = 0;
         act.sa_handler = handler;
-        while(sigaction(sig, &act, 0) && errno==EINTR);
+        while(sigaction(sig, &act, NULL) && errno==EINTR);
 }
 
 void signal_handle(int sig)