[libc++][doc] Documents -DLIBCXX_INSTALL_MODULES=ON. (#88547)

mordante · ldionne · web-flow · commit 8e0a4a89f940 · 2024-04-16T20:22:48.000+02:00
Co-authored-by: Louis Dionne &lt;ldionne.2@gmail.com&gt;
diff --git a/libcxx/docs/BuildingLibcxx.rst b/libcxx/docs/BuildingLibcxx.rst
@@ -206,6 +206,12 @@ libc++ specific options
 
   Toggle the installation of the libc++ headers.
 
+.. option:: LIBCXX_INSTALL_MODULES:BOOL
+
+  **Default**: ``OFF``
+
+  Toggle the installation of the experimental libc++ module sources.
+
 .. option:: LIBCXX_ENABLE_SHARED:BOOL
 
   **Default**: ``ON``
