VS: Add genex support to VS_SHADER_FLAGS

Source/cmVisualStudio10TargetGenerator.cxx

@@ -1897,8 +1897,15 @@ void cmVisualStudio10TargetGenerator::WriteExtraSource(Elem& e1,
     }
     // Figure out if there's any additional flags to use
     if (cmProp saf = sf->GetProperty("VS_SHADER_FLAGS")) {
+      cmGeneratorExpression ge;
+      std::unique_ptr<cmCompiledGeneratorExpression> cge = ge.Parse(*saf);
+
       for (const std::string& config : this->Configurations) {
-        toolSettings[config]["AdditionalOptions"] = *saf;
+        std::string evaluated = cge->Evaluate(this->LocalGenerator, config);
+
+        if (!evaluated.empty()) {
+          toolSettings[config]["AdditionalOptions"] = evaluated;
+        }
       }
     }
     // Figure out if debug information should be generated

Tests/VSWinStorePhone/CMakeLists.txt

@@ -119,13 +119,13 @@ set_property(SOURCE ${RELEASE_CONTENT_FILES} PROPERTY
 set_property(SOURCE ${PIXELSHADER_FILES} PROPERTY VS_SHADER_TYPE Pixel)
 set_property(SOURCE ${PIXELSHADER_FILES} PROPERTY VS_SHADER_ENTRYPOINT mainPS)
 set_property(SOURCE ${PIXELSHADER_FILES} PROPERTY VS_SHADER_MODEL 4.0_level_9_3)
-set_property(SOURCE ${PIXELSHADER_FILES} PROPERTY VS_SHADER_FLAGS "/DFLAGS_ADDED")
+set_property(SOURCE ${PIXELSHADER_FILES} PROPERTY VS_SHADER_FLAGS $<1:/DFLAGS_ADDED>)
 set_property(SOURCE ${PIXELSHADER_FILES} PROPERTY VS_SHADER_OUTPUT_HEADER_FILE "$(OutDir)%(Filename).h")
 
 set_property(SOURCE ${VERTEXSHADER_FILES} PROPERTY VS_SHADER_TYPE Vertex)
 set_property(SOURCE ${VERTEXSHADER_FILES} PROPERTY VS_SHADER_ENTRYPOINT mainVS)
 set_property(SOURCE ${VERTEXSHADER_FILES} PROPERTY VS_SHADER_MODEL 4.0_level_9_3)
-set_property(SOURCE ${VERTEXSHADER_FILES} PROPERTY VS_SHADER_FLAGS "/DFLAGS_ADDED")
+set_property(SOURCE ${VERTEXSHADER_FILES} PROPERTY VS_SHADER_FLAGS $<1:/DFLAGS_ADDED>)
 set_property(SOURCE ${VERTEXSHADER_FILES} PROPERTY VS_SHADER_OUTPUT_HEADER_FILE "$(OutDir)%(Filename).h")
 set_property(SOURCE ${VERTEXSHADER_FILES} PROPERTY VS_SETTINGS "$<$<CONFIG:DEBUG>:SourceProperty1=SourceProperty1Value>")