[compiler-rt] [rtsan] Make sure rtsan gets initialized on mac (PR #100188)

[Vitaly Buka via llvm-commits]

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@@ -39,7 +39,6 @@
 
 using namespace __sanitizer;
 
-using __rtsan::rtsan_init_is_running;
 using __rtsan::rtsan_initialized;
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vitalybuka wrote:

It would be better to use atomics here
see `static atomic_uint8_t asan_inited`

https://github.com/llvm/llvm-project/pull/100188