VS: Find Desktop SDK for current VS version (#15662)

Determine the Desktop SDK for Windows Phone and Windows Store from the
generator instead of the version of the targeted app.  This allows to
build a Windows Phone 8.1 app on VS 2015 for example.

Source/cmGlobalVisualStudio11Generator.h

@@ -34,9 +34,12 @@ protected:
   virtual bool SelectWindowsPhoneToolset(std::string& toolset) const;
   virtual bool SelectWindowsStoreToolset(std::string& toolset) const;
 
+  // Used to verify that the Desktop toolset for the current generator is
+  // installed on the machine.
+  virtual bool IsWindowsDesktopToolsetInstalled() const;
+
   // These aren't virtual because we need to check if the selected version
   // of the toolset is installed
-  bool IsWindowsDesktopToolsetInstalled() const;
   bool IsWindowsPhoneToolsetInstalled() const;
   bool IsWindowsStoreToolsetInstalled() const;
 

Source/cmGlobalVisualStudio12Generator.h

@@ -38,9 +38,12 @@ protected:
   virtual bool SelectWindowsPhoneToolset(std::string& toolset) const;
   virtual bool SelectWindowsStoreToolset(std::string& toolset) const;
 
+  // Used to verify that the Desktop toolset for the current generator is
+  // installed on the machine.
+  virtual bool IsWindowsDesktopToolsetInstalled() const;
+
   // These aren't virtual because we need to check if the selected version
   // of the toolset is installed
-  bool IsWindowsDesktopToolsetInstalled() const;
   bool IsWindowsPhoneToolsetInstalled() const;
   bool IsWindowsStoreToolsetInstalled() const;
   virtual const char* GetIDEVersion() { return "12.0"; }

Source/cmGlobalVisualStudio14Generator.cxx

@@ -124,3 +124,16 @@ void cmGlobalVisualStudio14Generator::WriteSLNHeader(std::ostream& fout)
     fout << "# Visual Studio 14\n";
     }
 }
+
+//----------------------------------------------------------------------------
+bool
+cmGlobalVisualStudio14Generator::IsWindowsDesktopToolsetInstalled() const
+{
+  const char desktop10Key[] =
+    "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\"
+    "VisualStudio\\14.0\\VC\\Runtimes";
+
+  std::vector<std::string> vc14;
+  return cmSystemTools::GetRegistrySubKeys(desktop10Key,
+    vc14, cmSystemTools::KeyWOW64_32);
+}

Source/cmGlobalVisualStudio14Generator.h

@@ -31,6 +31,11 @@ public:
   virtual const char* GetToolsVersion() { return "14.0"; }
 protected:
   virtual const char* GetIDEVersion() { return "14.0"; }
+
+  // Used to verify that the Desktop toolset for the current generator is
+  // installed on the machine.
+  virtual bool IsWindowsDesktopToolsetInstalled() const;
+
 private:
   class Factory;
 };