[libcxx-commits] [libcxx] [libc++][modules] Adds module testing. (PR #76246)

[Daniel Thornburgh via libcxx-commits]

mysterymath wrote:

Hey, it looks like we're seeing test failures on the Fuchsia Windows x64 clang builder due to this:
https://luci-milo.appspot.com/ui/p/fuchsia/builders/toolchain.ci/clang-windows-x64/b8758641350195498481/overview

E.g. for `llvm-libc++-static-clangcl.cfg.in :: libcxx/selftest/modules/std-and-std.compat-module.sh.cpp`:
```
# .---command stderr------------
# | C:/b/s/w/ir/x/w/llvm_build/modules/c++/v1/std.cppm:193:4: error: "please update the header information for <spanstream> in headers_not_available in utils/libcxx/header_information.py"
# |   193 | #  error "please update the header information for <spanstream> in headers_not_available in utils/libcxx/header_information.py"
# |       |    ^
# | C:/b/s/w/ir/x/w/llvm_build/modules/c++/v1/std.cppm:196:4: error: "please update the header information for <stacktrace> in headers_not_available in utils/libcxx/header_information.py"
# |   196 | #  error "please update the header information for <stacktrace> in headers_not_available in utils/libcxx/header_information.py"
# |       |    ^
# | In file included from C:/b/s/w/ir/x/w/llvm_build/modules/c++/v1/std.cppm:239:
# | C:/b/s/w/ir/x/w/llvm_build/modules/c++/v1\std/ctime.inc:20:14: error: using declaration referring to 'ctime' with internal linkage cannot be exported
# |    20 |   using std::ctime;
# |       |              ^
etc etc
```

https://github.com/llvm/llvm-project/pull/76246