[lld] [ELF] Fix unnecessary inclusion of unreferenced provide symbols (PR #84512)

[Fangrui Song via llvm-commits]

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@@ -2659,6 +2659,58 @@ static void postParseObjectFile(ELFFileBase *file) {
   }
 }
 
+// Returns true if the provide symbol should be added to the link.
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MaskRay wrote:

Add `static`

These functions can be moved to `LinkerScript.cpp`

`shouldDefineSym` can be refactored to use `shouldAddProvideSym`.

Newer code should use `sym` instead of `b`

https://github.com/llvm/llvm-project/pull/84512