Get sdktools and sdkhooks/dhooks to load on hl2sdk-mock (#1892)

* Build SDKTools for hl2sdk-mock

* Fix loading of extensions using advanced naming scheme for hl2sdk-mock

* Fix error on missing sv_visiblemaxplayers convar

* Build SDKHooks for hl2sdk-mock

* Fix x86_64 SourcePawn VM filename

* SDKHooks: Ignore missing IEntityListeners list in hl2sdk-mock

extensions/sdkhooks/AMBuilder

@@ -12,8 +12,6 @@ project.sources += [
 
 for sdk_name in SM.sdks:
   sdk = SM.sdks[sdk_name]
-  if sdk.name == 'mock':
-    continue
 
   for cxx in builder.targets:
     if not cxx.target.arch in sdk.platformSpec[cxx.target.platform]:

extensions/sdkhooks/extension.cpp

@@ -230,10 +230,15 @@ bool SDKHooks::SDK_OnLoad(char *error, size_t maxlength, bool late)
 	if (!entListeners)
 	{
 		g_pSM->Format(error, maxlength, "Failed to setup entity listeners");
+#if SOURCE_ENGINE != SE_MOCK
 		return false;
+#endif
+	}
+	else
+	{
+		entListeners->AddToTail(this);
 	}
 
-	entListeners->AddToTail(this);
 
 	sharesys->AddDependency(myself, "bintools.ext", true, true);
 	sharesys->AddNatives(myself, g_Natives);
@@ -367,7 +372,10 @@ void SDKHooks::SDK_OnUnload()
 	sharesys->DropCapabilityProvider(myself, this, "SDKHook_LogicalEntSupport");
 
 	CUtlVector<IEntityListener *> *entListeners = EntListeners();
-	entListeners->FindAndRemove(this);
+	if (entListeners)
+	{
+		entListeners->FindAndRemove(this);
+	}
 
 	gameconfs->CloseGameConfigFile(g_pGameConf);
 }