runtime/race package contains the data race detector runtime library.
It is based on ThreadSanitizer race detector, that is currently a part of
the LLVM project (http://llvm.org/git/compiler-rt.git).
To update the .syso files use golang.org/x/build/cmd/racebuild.
Current runtime is built on rev 68e1532492f9b3fce0e9024f3c31411105965b11.