[libc++][C++23 std module] Error in <string> when compiling std module on windows

[Arthapz]

Hello, here an other issue when we compile std module on windows

In module 'std' imported from src\mod.mpp:3:
C:\Dev\llvm\include\c++\v1\string:4319:21: error: no member named '__do_string_hash' in namespace 'std'
 4319 |         return std::__do_string_hash(__val.data(), __val.data() + __val.size());
      |  

here a self contained reproducer with full logs: https://github.com/Arthapz/libcpp-stdmodule-string-errors

> clang --version                                                                                                                                                                                                       
clang version 18.0.0 (https://github.com/llvm/llvm-project.git f6f6f1947da3fd088bd6f8b8d43a31d18ccd750f)
Target: x86_64-pc-windows-msvc
Thread model: posix
InstalledDir: C:\Dev\llvm\bin

[llvmbot]

@llvm/issue-subscribers-clang-modules

[ChuanqiXu9]

The root problems is that we don't handle modules well with -fdelayed-template-parsing.

[ChuanqiXu9]

Originally, I thought #69431 is simply a workaround. But according to the later discussions, I found it may be a proper solution since now we treat -fdelayed-template-parsing as a source of bugs. Then I think we can close the issue now. Feel free to reopen this if any one has different opinions.