[lld] [lld][COFF][LTO] Implement /opt:emitllvm option (PR #66964)

[Martin Storsjö via llvm-commits]

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@@ -10,11 +10,15 @@
 #define LLD_FILESYSTEM_H
 
 #include "lld/Common/LLVM.h"
+#include "llvm/Support/raw_ostream.h"
+#include <memory>
 #include <system_error>
 
 namespace lld {
 void unlinkAsync(StringRef path);
 std::error_code tryCreateFile(StringRef path);
+std::unique_ptr<llvm::raw_fd_ostream> openFile(StringRef file);
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mstorsjo wrote:

Could we have the refactoring of `openFile` and `openLTOOutputFile` in a separate preceding commit?

https://github.com/llvm/llvm-project/pull/66964