[libcxx-commits] [libcxx] [libc++][doc] Updates module build instructions. (PR #89413)

[Will Hawkins via libcxx-commits]

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@@ -105,9 +103,17 @@ Users need to be able to build their own BMI files.
    system vendors, with the goal that building the BMI files is done by
    the build system.
 
-Currently this requires a local build of libc++ with modules enabled. Since
-modules are not part of the installation yet, they are used from the build
-directory. First libc++ needs to be build with module support enabled.
+Currently there are two ways to build modules
+
+  * Use a local build of modules from the build directory. This requires
+    Clang 17 or later and CMake 3.26 or later.
+
+  * Use the installed modules. This requires Clang 18.1.2 or later and
+    a recent build of CMake. The CMake changes will be part CMake 3.30. This
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hawkinsw wrote:

```suggestion
    a recent build of CMake. The CMake changes will be part of CMake 3.30. This
```

https://github.com/llvm/llvm-project/pull/89413