[libcxx-commits] [libcxx] [RFC][libc++] Install modules. (PR #75741)

[Steve Downey via libcxx-commits]

================
@@ -424,6 +428,8 @@ set(LIBCXX_INSTALL_INCLUDE_DIR "${CMAKE_INSTALL_INCLUDEDIR}/c++/v1" CACHE STRING
     "Path where target-agnostic libc++ headers should be installed.")
 set(LIBCXX_INSTALL_RUNTIME_DIR "${CMAKE_INSTALL_BINDIR}" CACHE STRING
     "Path where built libc++ runtime libraries should be installed.")
+set(LIBCXX_INSTALL_MODULE_DIR "${CMAKE_INSTALL_INCLUDEDIR}/../modules/c++/v1" CACHE STRING
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steve-downey wrote:

usr is a $prefix, so probably intended as
```
$prefix/include/c++/v1/__private_modules/
$prefix/include/c++/v1/
$prefix/usr/share/libc++/v1/
etc
```

I see very few things in my usr/include that aren't textual inclusion for C or C++. There's some evidence that fortran may put mod files there, but it looks like rust puts similar information in share/cargo, which isn't a choice for C++. 



https://github.com/llvm/llvm-project/pull/75741