<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/60669>60669</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang-scan-deps fails to find stddef.h
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
      </td>
    </tr>

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

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

<pre>
    Given the following translation unit

```cpp
#include <stddef.h>
```

Running

```
clang-scan-deps -format=p1689 -- -std=c++20 a.cpp -o /dev/null > /dev/null
```

fails with 

```
Error while scanning dependencies for a.cpp:
a.cpp:1:10: fatal error: 'stddef.h' file not found
```

With a build at git revision 89197b59f597995ecb6b6dc2e262a1ecddeee901

Note that other includes work, so long as they do not transitively include stddef.h (and maybe other headers?). For instance, I can `#include <version>` just fine.
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJx8k8tu5CwQhZ8Gb0q2MHTbZuFFko5__ZtZzGbWGMo2GRoswN3qtx_Rl0wSjSL5okKuw3eoYxmjmR1iT_bPZH8o5JYWH3otT0bH5B0Wo9eX_j9zQgdpQZi8tf5s3AwpSBetTMY72JxJhB4Ifbo_G3q71LreVxg3TtlNIxD-EpPWOFUL4a9fGj6q_NycM27-p_CtVFa6uYxKulLjGqGcfDjKRPhhrZtOQFlCGZMm_KAIeybsmVGQlVpXKD0QNmg8ETa4zVog_PXzyjdgkzQ2wtmkBb6Bew3BBzgvxiJkxOwFNK7oNDplMMLkww2H8LvEo6rzTQl_gkkmaQGzVi4Ja98Pj7UwZXHnE0x-c_ob5F8ZVsK4GatBJphNgoAnE_P4OlGLdtyLaS9aIfaoxmZstGLIGiZrVFojoqD1R8EfPiGkRSbwacEA9-lGOPvwm7AXiB6sdzPImINzAe2voNfYmGROaC-PJnhYAsI66TQc5WXEu_CCUmOIhA-EiQoGn_eKSTqFeZv_QUkH2e2nhJ0wZGs5YA2Fty0mmIzDqtA914ILWWBfN21Dm452bbH0CmUnlJQ1HSfdCsa73X7iu7FFzhjd14XpGWWcspoyxjraViPv-E5zOXZYi1HUZEfxKI2trD0dKx_mwsS4Yd_QphGFlSPa-PjPQp8_KsdtjmRHrYkp_m1LJlnsv2b7Frrksw_9fmLFFmy_pLTGnCE2EDbMJi3bWCl_JGzIovdXuQb_hioRNlzBImHDle1PAAAA__9g4zk6">