Xcode: Remove remnants of ancient XCODE_DEPEND_HELPER utility target

The target has not been generated since commit d92d51429e (BUG: fix for bug
6193, fix xcode depend helper, 2008-01-10, v2.6.0~553).  Remove it from
the list of special targets.

Source/cmGlobalXCodeGenerator.cxx

@@ -1284,9 +1284,8 @@ cmXCodeObject* cmGlobalXCodeGenerator::CreateXCodeFileReference(
 
 bool cmGlobalXCodeGenerator::SpecialTargetEmitted(std::string const& tname)
 {
-  if (tname == "ALL_BUILD" || tname == "XCODE_DEPEND_HELPER" ||
-      tname == "install" || tname == "package" || tname == "RUN_TESTS" ||
-      tname == CMAKE_CHECK_BUILD_SYSTEM_TARGET) {
+  if (tname == "ALL_BUILD" || tname == "install" || tname == "package" ||
+      tname == "RUN_TESTS" || tname == CMAKE_CHECK_BUILD_SYSTEM_TARGET) {
     if (this->TargetDoneSet.find(tname) != this->TargetDoneSet.end()) {
       return true;
     }
@@ -3986,7 +3985,7 @@ bool cmGlobalXCodeGenerator::CreateXCodeObjects(
   for (auto t : targets) {
     this->AddDependAndLinkInformation(t);
   }
-  this->CreateXCodeDependHackTarget(targets);
+  this->CreateXCodeDependHackMakefile(targets);
   // now add all targets to the root object
   cmXCodeObject* allTargets = this->CreateObject(cmXCodeObject::OBJECT_LIST);
   for (auto t : targets) {
@@ -4046,7 +4045,7 @@ void cmGlobalXCodeGenerator::ComputeObjectDirArch(cmMakefile* mf)
   }
 }
 
-void cmGlobalXCodeGenerator::CreateXCodeDependHackTarget(
+void cmGlobalXCodeGenerator::CreateXCodeDependHackMakefile(
   std::vector<cmXCodeObject*>& targets)
 {
   cmGeneratedFileStream makefileStream(this->CurrentXCodeHackMakefile);

Source/cmGlobalXCodeGenerator.h

@@ -227,7 +227,7 @@ private:
                          std::vector<cmXCodeObject*>&);
   bool IsHeaderFile(cmSourceFile*);
   void AddDependTarget(cmXCodeObject* target, cmXCodeObject* dependTarget);
-  void CreateXCodeDependHackTarget(std::vector<cmXCodeObject*>& targets);
+  void CreateXCodeDependHackMakefile(std::vector<cmXCodeObject*>& targets);
   bool SpecialTargetEmitted(std::string const& tname);
   void SetGenerationRoot(cmLocalGenerator* root);
   void AddExtraTargets(cmLocalGenerator* root,