[clang] Fix --print-libgcc-file-name on Darwin platforms (PR #98325)

[Louis Dionne via cfe-commits]

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@@ -223,6 +223,11 @@ class LLVM_LIBRARY_VISIBILITY MachO : public ToolChain {
     // There aren't any profiling libs for embedded targets currently.
   }
 
+  // Return the full path of the compiler-rt library on a Darwin MachO system.
+  // Those are under <resourcedir>/lib/darwin/<...>(.dylib|.a).
+  std::string getCompilerRT(const llvm::opt::ArgList &Args, StringRef Component,
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ldionne wrote:

I actually don't know much about these targets, they're kinda mysterious to me TBH, so I don't know what to document.

https://github.com/llvm/llvm-project/pull/98325