VS: Add VS_WINRT_COMPONENT property to enable CompileAsWinRT

Deprecate VS_WINRT_EXTENSIONS and document VS_WINRT_COMPONENT as for VS
generators only.  Also define _WINRT_DLL in SHARED libraries in order to
get a .lib produced.

Inspired-by: Paul Annetts <paul@lightunobscured.com>

Help/manual/cmake-properties.7.rst

@@ -235,6 +235,7 @@ Properties on Targets
    /prop_tgt/VS_SCC_LOCALPATH
    /prop_tgt/VS_SCC_PROJECTNAME
    /prop_tgt/VS_SCC_PROVIDER
+   /prop_tgt/VS_WINRT_COMPONENT
    /prop_tgt/VS_WINRT_EXTENSIONS
    /prop_tgt/VS_WINRT_REFERENCES
    /prop_tgt/WIN32_EXECUTABLE

Help/prop_tgt/VS_WINRT_COMPONENT.rst

@@ -0,0 +1,14 @@
+VS_WINRT_COMPONENT
+------------------
+
+Mark a target as a Windows Runtime component for the Visual Studio generator.
+Compile the target with ``C++/CX`` language extensions for Windows Runtime.
+For ``SHARED`` and ``MODULE`` libraries, this also defines the
+``_WINRT_DLL`` preprocessor macro.
+
+.. note::
+  Behavior is not defined for targets with source files that compile as
+  any language other than ``CXX``.
+
+  Currently this is implemented only by Visual Studio generators.
+  Support may be added to other generators in the future.

Help/prop_tgt/VS_WINRT_EXTENSIONS.rst

@@ -1,6 +1,5 @@
 VS_WINRT_EXTENSIONS
 -------------------
 
-Visual Studio project C++/CX language extensions for Windows Runtime
-
-Can be set to enable C++/CX language extensions.
+Deprecated.  Use :prop_tgt:`VS_WINRT_COMPONENT` instead.
+This property was an experimental partial implementation of that one.

Source/cmVisualStudio10TargetGenerator.cxx

@@ -591,6 +591,7 @@ void cmVisualStudio10TargetGenerator
 
   if((this->Target->GetType() <= cmTarget::OBJECT_LIBRARY &&
       this->ClOptions[config]->UsingUnicode()) ||
+     this->Target->GetPropertyAsBool("VS_WINRT_COMPONENT") ||
      this->Target->GetPropertyAsBool("VS_WINRT_EXTENSIONS"))
     {
     this->WriteString("<CharacterSet>Unicode</CharacterSet>\n", 2);
@@ -611,7 +612,8 @@ void cmVisualStudio10TargetGenerator
     pts += "</PlatformToolset>\n";
     this->WriteString(pts.c_str(), 2);
     }
-  if(this->Target->GetPropertyAsBool("VS_WINRT_EXTENSIONS"))
+  if(this->Target->GetPropertyAsBool("VS_WINRT_COMPONENT") ||
+     this->Target->GetPropertyAsBool("VS_WINRT_EXTENSIONS"))
     {
     this->WriteString("<WindowsAppContainer>true"
                       "</WindowsAppContainer>\n", 2);
@@ -1604,6 +1606,29 @@ bool cmVisualStudio10TargetGenerator::ComputeClOptions(
     clOptions.AddDefine(exportMacro);
     }
 
+  if (this->MSTools)
+    {
+    // If we have the VS_WINRT_COMPONENT set then force Compile as WinRT.
+    if (this->Target->GetPropertyAsBool("VS_WINRT_COMPONENT"))
+      {
+      clOptions.AddFlag("CompileAsWinRT", "true");
+      // For WinRT components, add the _WINRT_DLL define to produce a lib
+      if (this->Target->GetType() == cmTarget::SHARED_LIBRARY ||
+          this->Target->GetType() == cmTarget::MODULE_LIBRARY )
+        {
+        clOptions.AddDefine("_WINRT_DLL");
+        }
+      }
+    else if (this->GlobalGenerator->TargetsWindowsStore() ||
+             this->GlobalGenerator->TargetsWindowsPhone())
+      {
+      if (!clOptions.IsWinRt())
+        {
+        clOptions.AddFlag("CompileAsWinRT", "false");
+        }
+      }
+    }
+
   this->ClOptions[configName] = pOptions.release();
   return true;
 }

Source/cmVisualStudioGeneratorOptions.cxx

@@ -106,6 +106,12 @@ bool cmVisualStudioGeneratorOptions::IsDebug() const
   return this->FlagMap.find("DebugInformationFormat") != this->FlagMap.end();
 }
 
+//----------------------------------------------------------------------------
+bool cmVisualStudioGeneratorOptions::IsWinRt() const
+{
+  return this->FlagMap.find("CompileAsWinRT") != this->FlagMap.end();
+}
+
 //----------------------------------------------------------------------------
 bool cmVisualStudioGeneratorOptions::UsingUnicode() const
 {

Source/cmVisualStudioGeneratorOptions.h

@@ -52,6 +52,7 @@ public:
   bool UsingSBCS() const;
 
   bool IsDebug() const;
+  bool IsWinRt() const;
   // Write options to output.
   void OutputPreprocessorDefinitions(std::ostream& fout,
                                      const char* prefix,