Autogen: Evaluate compiler features for the same exectuable only once

To speed up the `AUTOGEN` configuration process, evaluate the compiler
features only once.  The feature evaluation result is stored in the new class
`cmQtAutoGen::CompilerFeatures`, and the instance is shared by using
`std::shared_ptr`.

1 files changed, 10 insertions, 0 deletions

diff --git a/Source/cmQtAutoGen.h b/Source/cmQtAutoGen.h
index 3a346b5..9c52129 100644
--- a/Source/cmQtAutoGen.h
+++ b/Source/cmQtAutoGen.h
@@ -5,6 +5,7 @@
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
+#include <memory> // IWYU pragma: keep
 #include <string>
 #include <vector>
 
@@ -40,6 +41,15 @@ public:
     }
   };
 
+  class CompilerFeatures
+  {
+  public:
+    bool Evaluated = false;
+    std::string HelpOutput;
+    std::vector<std::string> ListOptions;
+  };
+  typedef std::shared_ptr<CompilerFeatures> CompilerFeaturesHandle;
+
   /// @brief AutoGen generator type
   enum class GenT
   {