url: Build WinRT-specific code as C++/CX instead of plain C++.

VisualC-WinRT/UWP_VS2015/SDL-UWP.vcxproj

@@ -255,7 +255,14 @@
     <ClCompile Include="..\..\src\locale\SDL_locale.c" />
     <ClCompile Include="..\..\src\locale\winrt\SDL_syslocale.c" />
     <ClCompile Include="..\..\src\misc\SDL_url.c" />
-    <ClCompile Include="..\..\src\misc\winrt\SDL_sysurl.cpp" />
+    <ClCompile Include="..\..\src\misc\winrt\SDL_sysurl.cpp">
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</CompileAsWinRT>
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Debug|ARM'">true</CompileAsWinRT>
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">true</CompileAsWinRT>
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">true</CompileAsWinRT>
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Release|ARM'">true</CompileAsWinRT>
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Release|x64'">true</CompileAsWinRT>
+    </ClCompile>
     <ClCompile Include="..\..\src\power\SDL_power.c" />
     <ClCompile Include="..\..\src\power\winrt\SDL_syspower.cpp" />
     <ClCompile Include="..\..\src\render\direct3d11\SDL_render_d3d11.c" />

VisualC-WinRT/WinPhone81_VS2013/SDL-WinPhone81.vcxproj

@@ -251,7 +251,12 @@
     <ClCompile Include="..\..\src\locale\SDL_locale.c" />
     <ClCompile Include="..\..\src\locale\winrt\SDL_syslocale.c" />
     <ClCompile Include="..\..\src\misc\SDL_url.c" />
-    <ClCompile Include="..\..\src\misc\winrt\SDL_sysurl.cpp" />
+    <ClCompile Include="..\..\src\misc\winrt\SDL_sysurl.cpp">
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</CompileAsWinRT>
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Debug|ARM'">true</CompileAsWinRT>
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">true</CompileAsWinRT>
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Release|ARM'">true</CompileAsWinRT>
+    </ClCompile>
     <ClCompile Include="..\..\src\sensor\dummy\SDL_dummysensor.c" />
     <ClCompile Include="..\..\src\sensor\SDL_sensor.c" />
     <ClCompile Include="..\..\src\stdlib\SDL_getenv.c" />

VisualC-WinRT/WinRT81_VS2013/SDL-WinRT81.vcxproj

@@ -283,7 +283,14 @@
     <ClInclude Include="..\..\src\locale\SDL_locale.c" />
     <ClInclude Include="..\..\src\locale\winrt\SDL_syslocale.c" />
     <ClCompile Include="..\..\src\misc\SDL_url.c" />
-    <ClCompile Include="..\..\src\misc\winrt\SDL_sysurl.cpp" />
+    <ClCompile Include="..\..\src\misc\winrt\SDL_sysurl.cpp">
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</CompileAsWinRT>
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Debug|ARM'">true</CompileAsWinRT>
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">true</CompileAsWinRT>
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">true</CompileAsWinRT>
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Release|ARM'">true</CompileAsWinRT>
+      <CompileAsWinRT Condition="'$(Configuration)|$(Platform)'=='Release|x64'">true</CompileAsWinRT>
+    </ClCompile>
     <ClCompile Include="..\..\src\sensor\dummy\SDL_dummysensor.c" />
     <ClCompile Include="..\..\src\sensor\SDL_sensor.c" />
     <ClCompile Include="..\..\src\stdlib\SDL_getenv.c" />