Battery (Haiku): handle empty slots

My ThinkPad has a second slot for external batteries.

Author: mmuman

src/detection/battery/battery_haiku.c

@@ -34,7 +34,14 @@ const char* parseBattery(int dfd, const char* battId, FFlist* results)
         ffStrbufAppendS(&battery->status, "Discharging, ");
     if (basic.state & BATTERY_CHARGING)
         ffStrbufAppendS(&battery->status, "Charging, ");
-    if (basic.state & BATTERY_CRITICAL_STATE)
+    if (basic.state & BATTERY_CRITICAL_STATE &&
+        strlen(extended.model_number) == 0 &&
+        strlen(extended.serial_number) == 0 &&
+        strlen(extended.type) == 0 &&
+        strlen(extended.oem_info) == 0
+    )
+        ffStrbufAppendS(&battery->status, "Not populated, ");
+    else if (basic.state & BATTERY_CRITICAL_STATE)
         ffStrbufAppendS(&battery->status, "Critical, ");
     if (basic.state & BATTERY_NOT_CHARGING)
         ffStrbufAppendS(&battery->status, "AC Connected, ");