[compiler-rt] [TSan] Fix warning when compiling with -Wmissing-designated-field-initializers (PR #163401)

[Julian Lettner via llvm-commits]

================
@@ -259,7 +259,9 @@ void InitializePlatform() {
 
   ThreadEventCallbacks callbacks = {
       .create = ThreadCreateCallback,
+      .start = nullptr,
       .terminate = ThreadTerminateCallback,
+      .destroy = nullptr,
----------------
yln wrote:

Interesting.  I thought unmentioned members are guaranteed to be default-initialized.

The semantics of the warning seem to be under discussion:
https://github.com/llvm/llvm-project/issues/68933
https://github.com/llvm/llvm-project/issues/56628

Did this warning pop up with a new version of Clang or was it always there?

https://github.com/llvm/llvm-project/pull/163401