[clang] [clang][CodeGen] Emit lifetime markers for block-scoped compound literals in C (PR #219045)

[Eli Friedman via cfe-commits]

efriedma-quic wrote:

There's a stupid edge case here which this doesn't take into account:


```
int f() {
  int *p = 0;
label:
  if (p) return *p;
  p = &(int){10};
  goto label;
}
```

https://github.com/llvm/llvm-project/pull/219045