Autogen: Don't add a WIN32 moc definition if we have a moc_predefs.h …

…file

On Windows systems we used to add a "-DWIN32" definition to the ``moc``
defines.  This is not necessary anymore when we have a
``moc_predefs.h`` file that provides all compiler predefines.

Closes #18623

Source/cmQtAutoGenInitializer.cxx

@@ -521,6 +521,12 @@ bool cmQtAutoGenInitializer::InitMoc()
       [this, localGen](std::string const& cfg) -> std::set<std::string> {
       std::set<std::string> defines;
       localGen->GetTargetDefines(this->Target, cfg, "CXX", defines);
+#ifdef _WIN32
+      if (this->Moc.PredefsCmd.empty()) {
+        // Add WIN32 definition if we don't have a moc_predefs.h
+        defines.insert("WIN32");
+      }
+#endif
       return defines;
     };
 

Source/cmQtAutoGeneratorMocUic.cxx

@@ -1279,16 +1279,6 @@ bool cmQtAutoGeneratorMocUic::Init(cmMakefile* makefile)
       Moc_.SkipList.insert(lst.begin(), lst.end());
     }
     Moc_.Definitions = InfoGetConfigList("AM_MOC_DEFINITIONS");
-#ifdef _WIN32
-    {
-      std::string win32("WIN32");
-      auto itB = Moc().Definitions.cbegin();
-      auto itE = Moc().Definitions.cend();
-      if (std::find(itB, itE, win32) == itE) {
-        Moc_.Definitions.emplace_back(std::move(win32));
-      }
-    }
-#endif
     Moc_.IncludePaths = InfoGetConfigList("AM_MOC_INCLUDES");
     Moc_.Options = InfoGetList("AM_MOC_OPTIONS");
     Moc_.RelaxedMode = InfoGetBool("AM_MOC_RELAXED_MODE");