Fix building on MSVC & fix a double-free crash

JacksEscape.vcxproj

@@ -139,6 +139,7 @@
     <ClInclude Include="entity.h" />
     <ClInclude Include="gametime.h" />
     <ClInclude Include="input.h" />
+    <ClInclude Include="leaderboards.h" />
     <ClInclude Include="mapper_misc.h" />
     <ClInclude Include="particle.h" />
     <ClInclude Include="physics.h" />
@@ -166,6 +167,8 @@
     <ClCompile Include="entity.c" />
     <ClCompile Include="gametime.c" />
     <ClCompile Include="input.c" />
+    <ClCompile Include="leaderboards.c" />
+    <ClCompile Include="leaderboards_file.c" />
     <ClCompile Include="main.cpp" />
     <ClCompile Include="mapper_misc.c" />
     <ClCompile Include="mapper_misc_render.cpp" />

JacksEscape.vcxproj.filters

@@ -84,6 +84,9 @@
     <ClInclude Include="ui.h">
       <Filter>头文件</Filter>
     </ClInclude>
+    <ClInclude Include="leaderboards.h">
+      <Filter>头文件</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="util\queue.c">
@@ -188,5 +191,11 @@
     <ClCompile Include="ui_boxbuilder.c">
       <Filter>源文件</Filter>
     </ClCompile>
+    <ClCompile Include="leaderboards.c">
+      <Filter>源文件</Filter>
+    </ClCompile>
+    <ClCompile Include="leaderboards_file.c">
+      <Filter>源文件</Filter>
+    </ClCompile>
   </ItemGroup>
 </Project>

ui_build.c

@@ -70,6 +70,7 @@ static void _ui_Action_EndIntermission(System_UI *sys, ui_Part *part, uintptr_t
 		// should be able to just use this
 		_ui_Action_SelectLevel(sys, part, data);
 		free((void *)data);
+		((ui_Button *)part->user)->callback_data = NULL;
 	}
 }