message: rocfft_aot_helper: force sub-process compile
  Works around asserts in multithreaded hipRTC.
diff: @@ -230,6 +230,9 @@ int main(int argc, char** argv)
  // tell RTC where the compile helper is
  rocfft_setenv("ROCFFT_RTC_PROCESS_HELPER", rtc_helper.c_str());
  + // force RTC to use subprocess, to work around asserts when combining multithreading + hipRTC
  + rocfft_setenv("ROCFFT_RTC_PROCESS", "1");
  +
  RTCCache::single = std::make_unique<RTCCache>();
  CompileQueue queue;
  