[libc-commits] [libc] [libc] [doc] explain the need of `clang` (PR #74855)

[via libc-commits]

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@@ -60,9 +60,12 @@ to use the freshly built lld and compiler-rt.
 We will go over some of the special options passed to the ``cmake`` command
 above.
 
-* **Enabled Projects** - Since we want to build and install clang, lld
-  and compiler-rt along with the libc, we specify
-  ``clang;libc;lld;compiler-rt`` as the list of enabled projects.
+* **Enabled Projects** - Since we want to build and install ``clang``, ``lld``
+  and ``compiler-rt`` along with the ``libc``, we specify
+  ``clang;libc;lld;compiler-rt`` as the list of enabled projects. ``clang`` is 
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michaelrj-google wrote:

we can build with GCC, but we also need headergen to generate the headers and that currently is build with tablegen. It is possible to just build it separately and then use it with `-DLIBC_HDRGEN_EXE=/path/to/hdrgen` in your cmake.

As for TableGen, I'm pretty sure it's in `llvm/utils/TableGen`, so including `clang` shouldn't effect it either way.

https://github.com/llvm/llvm-project/pull/74855