<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/124152>124152</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [libc] add btowc to wchar.h generated header
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            good first issue,
            libc
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          nickdesaulniers
      </td>
    </tr>
</table>

<pre>
    While working on #124150, I noticed that libc/include/wchar.yaml is missing an entry for `btowc`, even though we have it implemented (libc/src/wchar/btowc.cpp). If we don't advertise it in the generated wchar.h, then users will get a diagnostic when calling it.
</pre>
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