-Werror,-Wwritable-strings (clang-cl)

Change-Id: I67287498db35c60f224b095b00e6c058f53c10cf
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/86471
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
diff --git a/setup_native/source/win32/customactions/reg_dlls/reg_dlls.cxx b/setup_native/source/win32/customactions/reg_dlls/reg_dlls.cxx
index 250a81b..74a524e 100644
--- a/setup_native/source/win32/customactions/reg_dlls/reg_dlls.cxx
+++ b/setup_native/source/win32/customactions/reg_dlls/reg_dlls.cxx
@@ -128,7 +128,7 @@ std::wstring MsiGetPropertyW(MSIHANDLE hInst, LPCWSTR szName)
{
    std::wstring sResult;
    DWORD nSz = 0;
    UINT nRet = ::MsiGetPropertyW(hInst, szName, L"", &nSz);
    UINT nRet = ::MsiGetPropertyW(hInst, szName, const_cast<wchar_t*>(L""), &nSz);
    if (nRet == ERROR_MORE_DATA)
    {
        ++nSz;
@@ -284,7 +284,8 @@ extern "C" __declspec(dllexport) UINT __stdcall PrepRegUnregDLLs(MSIHANDLE hInst
                throw std::exception("MsiCreateRecord failed!");
            MsiRecordSetStringW(hRec, 0, sVal.c_str());
            DWORD nSz = 0;
            if (MsiFormatRecordW(hInstall, hRec, L"", &nSz) == ERROR_MORE_DATA)
            if (MsiFormatRecordW(hInstall, hRec, const_cast<wchar_t*>(L""), &nSz)
                == ERROR_MORE_DATA)
            {
                ++nSz;
                auto buf = std::make_unique<wchar_t[]>(nSz);