Remove battery

I get this error when trying to build my NixOS system with the nixos-25.05 channel:

dwmstatus.c: In function 'gettemperature':
dwmstatus.c:182:24: error: returning 'char *' from a function with return type 'int' makes integer from pointer without a cast []
  182 |                 return smprintf("");
      |                        ^~~~~~~~~~~~

dwmstatus.c

@@ -20,7 +20,6 @@
 char *tzargentina = "America/Buenos_Aires";
 char *tzutc = "UTC";
 char *tzberlin = "Europe/Berlin";
-char *tzaustin = "America/Mexico_City";
 
 static Display *dpy;
 
@@ -180,9 +179,8 @@ gettemperature(char *base, char *sensor)
 
 	co = readfile(base, sensor);
 	if (co == NULL)
-		return smprintf("");
+		return 0;
 	return atof(co) / 1000;
-	// return smprintf("%02.0f°C", atof(co) / 1000);
 }
 
 char *
@@ -228,17 +226,17 @@ main(void)
 
 	for (;;sleep(30)) {
 		avgs = loadavg();
-		bat = getbattery("/sys/class/power_supply/BAT0");
+		// bat = getbattery("/sys/class/power_supply/BAT0");
 		// tmar = mktimes("%H:%M", tzargentina);
 		// tmutc = mktimes("%H:%M", tzutc);
-		tmbln = mktimes("%a %d %b %H:%M %Z %Y", tzaustin);
+		tmbln = mktimes("%a %d %b %H:%M %Z %Y", tzberlin);
 		// kbmap = execscript("setxkbmap -query | grep layout | cut -d':' -f 2- | tr -d ' '");
 		// surfs = execscript("surf-status");
 		t0 = gettemperature("/sys/devices/virtual/thermal/thermal_zone0", "temp");
 		t1 = gettemperature("/sys/devices/virtual/thermal/thermal_zone1", "temp");
     freeMem = execscript("free -m | grep Mem | awk '{ print $3 }'");
 
-		status = smprintf("| %d°C | %s | %sM | %s | %s |", t0 > t1 ? t0 : t1, avgs, freeMem, bat, tmbln);
+		status = smprintf("| %d°C | %s | %sM | %s |", t0 > t1 ? t0 : t1, avgs, freeMem, tmbln);
 		setstatus(status);
 
 		// free(surfs);
@@ -246,7 +244,7 @@ main(void)
 		// free(t0);
 		// free(t1);
 		free(avgs);
-		free(bat);
+		// free(bat);
 		// free(tmar);
 		// free(tmutc);
 		free(tmbln);