llvm-project

e40ff72d - [TSan][test-only] Make TSan os_unfair_lock.c test check the weak symbol before usage (#161173)

[TSan][test-only] Make TSan os_unfair_lock.c test check the weak symbol before usage (#161173) The os_unfair_lock.c test can currently fail with a null dereference if compiled on a platform with `os_unfair_lock_lock_with_flags`, but then executed on a platform without the function. This patch fixes this by first checking whether the symbol exists, and falls back to `os_unfair_lock_lock` if not. rdar://160596542