[lld] [lld] Add explicit std::move(...) to avoid a few vector copies (PR #180474)

[via llvm-commits]

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@@ -1339,7 +1339,7 @@ void LinkerDriver::parsePDBAltPath() {
     cursor = secondMark + 1;
   }
 
-  ctx.config.pdbAltPath = buf;
+  ctx.config.pdbAltPath = std::move(buf);
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serge-sans-paille wrote:

Actually we cannot work in place as the buffer computation involves referencing the old value for `ctx.config.pdbAltPath`

https://github.com/llvm/llvm-project/pull/180474