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

@@ -179,9 +179,8 @@ gettemperature(char *base, char *sensor)
 
 	co = readfile(base, sensor);
 	if (co == NULL)
-		return smprintf("");
+		return 0;
-  return atof(co) / 1000;
+	return atof(co) / 1000;
-	// return smprintf("%02.0f°C", atof(co) / 1000);
 }
 
 char *
@@ -227,7 +226,7 @@ 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", tzberlin);
@@ -245,7 +244,7 @@ main(void)
 		// free(t0);
 		// free(t1);
 		free(avgs);
-		free(bat);
+		// free(bat);
 		// free(tmar);
 		// free(tmutc);
 		free(tmbln);