[llvm] [lldb] DEBUGINFOD based DWP acquisition for LLDB (PR #70996)

[Kevin Frei via llvm-commits]

kevinfrei wrote:

> This breaks targeting macOS versions older than 10.12 for unnecessary reasons:
> 
> ```
> ../../llvm/lib/Debuginfod/Debuginfod.cpp:54:6: error: 'shared_mutex' is unavailable: introduced in macOS 10.12
> std::shared_mutex UrlsMutex;
>      ^
> ```
> 
> You should be able to use llvm::sys::RWMutex so please switch to that. See https://reviews.llvm.org/D138423 for an example.

Noooooooooooo!

I'll get this fixed up ASAP. Should I open an issue, or just put up a new PR? (Thanks for the example!)

https://github.com/llvm/llvm-project/pull/70996