Autogen: Defer setup until Generate step

It is better to set variables up once all target dependencies are known.

Source/cmGlobalGenerator.cxx

@@ -1544,8 +1544,9 @@ bool cmGlobalGenerator::Compute()
   }
 
 #ifndef CMAKE_BOOTSTRAP
-  cmQtAutoGenGlobalInitializer qtAutoGen(this->LocalGenerators);
+  this->QtAutoGen =
-  if (!qtAutoGen.InitializeCustomTargets()) {
+    cm::make_unique<cmQtAutoGenGlobalInitializer>(this->LocalGenerators);
+  if (!this->QtAutoGen->InitializeCustomTargets()) {
     return false;
   }
 #endif
@@ -1565,12 +1566,6 @@ bool cmGlobalGenerator::Compute()
     }
   }
 
-#ifndef CMAKE_BOOTSTRAP
-  if (!qtAutoGen.SetupCustomTargets()) {
-    return false;
-  }
-#endif
-
   for (const auto& localGen : this->LocalGenerators) {
     cmMakefile* mf = localGen->GetMakefile();
     for (const auto& g : mf->GetInstallGenerators()) {
@@ -1635,6 +1630,17 @@ void cmGlobalGenerator::Generate()
 
   this->CMakeInstance->UpdateProgress("Generating", 0.1f);
 
+#ifndef CMAKE_BOOTSTRAP
+  if (!this->QtAutoGen->SetupCustomTargets()) {
+    if (!cmSystemTools::GetErrorOccurredFlag()) {
+      this->GetCMakeInstance()->IssueMessage(
+        MessageType::FATAL_ERROR,
+        "Problem setting up custom targets for QtAutoGen");
+    }
+    return;
+  }
+#endif
+
   // Generate project files
   for (unsigned int i = 0; i < this->LocalGenerators.size(); ++i) {
     this->SetCurrentMakefile(this->LocalGenerators[i]->GetMakefile());

Source/cmGlobalGenerator.h

@@ -50,6 +50,7 @@ class cmLinkLineComputer;
 class cmLocalGenerator;
 class cmMakefile;
 class cmOutputConverter;
+class cmQtAutoGenGlobalInitializer;
 class cmSourceFile;
 class cmState;
 class cmStateDirectory;
@@ -683,6 +684,11 @@ protected:
   cmake* CMakeInstance;
   std::vector<std::unique_ptr<cmMakefile>> Makefiles;
   LocalGeneratorVector LocalGenerators;
+
+#ifndef CMAKE_BOOTSTRAP
+  std::unique_ptr<cmQtAutoGenGlobalInitializer> QtAutoGen;
+#endif
+
   cmMakefile* CurrentConfigureMakefile;
   // map from project name to vector of local generators in that project
   std::map<std::string, std::vector<cmLocalGenerator*>> ProjectMap;