Added IMC message to notify OC of a 3rd party power system. Closes #1784.

src/main/java/li/cil/oc/api/IMC.java

@@ -361,6 +361,17 @@ public final class IMC {
         FMLInterModComms.sendMessage(MOD_ID, "blacklistHost", nbt);
     }
 
+    /**
+     * Notifies OpenComputers that there is some 3rd-party power system present
+     * that adds integration on its side.
+     * <p/>
+     * This will suppress the "no power system found" message on start up, and
+     * avoid auto-disabling power use.
+     */
+    public static void registerCustomPowerSystem() {
+        FMLInterModComms.sendMessage(MOD_ID, "registerCustomPowerSystem", "true");
+    }
+
     // ----------------------------------------------------------------------- //
 
     private static final String MOD_ID = "OpenComputers";

src/main/scala/li/cil/oc/Settings.scala

@@ -135,8 +135,9 @@ class Settings(val config: Config) {
 
   // ----------------------------------------------------------------------- //
   // power
+  var is3rdPartyPowerSystemPresent = false
   val pureIgnorePower = config.getBoolean("power.ignorePower")
-  lazy val ignorePower = pureIgnorePower || !Mods.isPowerProvidingModPresent
+  lazy val ignorePower = pureIgnorePower || (!is3rdPartyPowerSystemPresent && !Mods.isPowerProvidingModPresent)
   val tickFrequency = config.getDouble("power.tickFrequency") max 1
   val chargeRateExternal = config.getDouble("power.chargerChargeRate")
   val chargeRateTablet = config.getDouble("power.chargerChargeRateTablet")

src/main/scala/li/cil/oc/common/IMC.scala

@@ -90,6 +90,9 @@ object IMC {
           case t: Throwable => OpenComputers.log.warn("Failed registering ink provider.", t)
         }
       }
+      else if (message.key == "registerCustomPowerSystem" && message.isStringMessage) {
+        Settings.get.is3rdPartyPowerSystemPresent = message.getStringValue == "true"
+      }
       else {
         OpenComputers.log.warn(s"Got an unrecognized or invalid IMC message '${message.key}' from mod ${message.getSender}.")
       }