[clang-tools-extra] `clangd`: support `-stdlib=` flags from `compile_commands.json`. (PR #69283)

[Chris Carlon via cfe-commits]

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@@ -203,6 +214,7 @@ template <> struct DenseMapInfo<DriverArgs> {
         Val.Driver,
         Val.StandardIncludes,
         Val.StandardCXXIncludes,
+        Val.Stdlib,
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cjc25 wrote:

Done, and resorted these to match the order in `DriverArgs` definition so it'll be easier to tell when things are missing in the future.

https://github.com/llvm/llvm-project/pull/69283