fix: build error(msvc 19.6)

msvc/ucxxrt.vcxproj

@@ -35,6 +35,7 @@
     </ProjectConfiguration>
   </ItemGroup>
   <ItemGroup>
+    <ClInclude Include="..\src\crt\stl\init_locks.hpp" />
     <ClInclude Include="..\src\crt\stl\primitives.hpp" />
     <ClInclude Include="..\src\crt\stl\xmath.hpp" />
     <ClInclude Include="..\src\crt\stl\xmtx.hpp" />

msvc/ucxxrt.vcxproj.filters

@@ -124,6 +124,9 @@
     <ClInclude Include="..\src\crt\stl\xmtx.hpp">
       <Filter>ucxxrt\crt\stl</Filter>
     </ClInclude>
+    <ClInclude Include="..\src\crt\stl\init_locks.hpp">
+      <Filter>ucxxrt\crt\stl</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <None Include="..\src\ucxxrt.inl">

src/crt/stl/init_locks.hpp

@@ -0,0 +1,31 @@
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#pragma once
+
+#include <yvals.h>
+
+_STD_BEGIN
+
+class _CRTIMP2_PURE_IMPORT _Init_locks { // initialize mutexes
+public:
+#ifdef _M_CEE_PURE
+    __CLR_OR_THIS_CALL _Init_locks() noexcept {
+        _Init_locks_ctor(this);
+    }
+
+    __CLR_OR_THIS_CALL ~_Init_locks() noexcept {
+        _Init_locks_dtor(this);
+    }
+
+#else // _M_CEE_PURE
+    __thiscall _Init_locks() noexcept;
+    __thiscall ~_Init_locks() noexcept;
+#endif // _M_CEE_PURE
+
+private:
+    static void __cdecl _Init_locks_ctor(_Init_locks*) noexcept;
+    static void __cdecl _Init_locks_dtor(_Init_locks*) noexcept;
+};
+
+_STD_END

src/crt/stl/xlock.cpp

@@ -8,6 +8,9 @@
 #include <clocale>
 #include <cstdlib>
 
+#if _MSC_VER >= 1936 // 17.6
+#include "init_locks.hpp"
+#endif
 #include "xmtx.hpp"
 
 _STD_BEGIN