<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/135459>135459</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [compiler-rt] CMake 4.0.x breaks build on macOS
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          1cebp
      </td>
    </tr>
</table>

<pre>
    CMake 4.0.x breaks compiler-rt during the second stage configure step.

It looks like the new version doesn't properly pass -isysroot=... to configuration targets on macOS, causing the build to fail.

```
[build] -- Got ld supported ARCHES: armv6 armv7 armv7s arm64 arm64e arm64_32 i386 x86_64 x86_64h armv6m armv7k armv7m armv7em
[build] -- Toolchain supported arches: armv6;armv7;armv7s;arm64;arm64e;arm64_32;i386;x86_64;x86_64h;armv6m;armv7k;armv7m;armv7em
[build] -- Using cached valid architectures for osx.
[build] -- OSX supported arches: arm64;arm64e;x86_64;x86_64h
[build] -- Compiler-RT supported architectures: arm64;arm64e;x86_64;x86_64h
[build] -- Host linker version: 1167.4.1
[build] CMake Error at /Users/icebp/llvm/compiler-rt/CMakeLists.txt:500 (message):
[build]   -g is not supported by host compiler
[build] 
[build] 
[build] -- Configuring incomplete, errors occurred!
[build] FAILED: runtimes/runtimes-stamps/runtimes-configure /Users/icebp/llvm/build/runtimes/runtimes-stamps/runtimes-configure 
```

Downstream users have mitigated by adding -isysroot manually.
https://github.com/microsoft/vcpkg/pull/44712
</pre>
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