[compiler-rt] [fuzzer][Fuchsia] Prevent deadlock from suspending threads (PR #154854)

[Petr Hosek via llvm-commits]

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@@ -68,6 +68,9 @@ void ExitOnErr(zx_status_t Status, const char *Syscall) {
 }
 
 void AlarmHandler(int Seconds) {
+  // Signal the alarm thread started.
+  ExitOnErr(_zx_object_signal(SignalHandlerEvent, 0, ZX_USER_SIGNAL_0),
+            "_zx_object_signal AlarmHandler");
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petrhosek wrote:

Nit for consistency with other error messages.
```suggestion
            "_zx_object_signal alarm");
```

https://github.com/llvm/llvm-project/pull/154854