[compiler-rt] [compiler-rt][rtsan] Fix recvmmsg rtsan interceptor for glibc < 2.21 (PR #123664)

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appujee wrote:

This is not sufficient as musl targets are still failing, please look at [the issue](https://github.com/llvm/llvm-project/issues/123689#issuecomment-2605759226) 

https://github.com/llvm/llvm-project/pull/123664