diff --git a/llvm/lib/Support/Watchdog.cpp b/llvm/lib/Support/Watchdog.cpp
index 724aa00..5facd40 100644
--- a/llvm/lib/Support/Watchdog.cpp
+++ b/llvm/lib/Support/Watchdog.cpp
@@ -18,6 +18,6 @@
 #ifdef LLVM_ON_UNIX
 #include "Unix/Watchdog.inc"
 #endif
-#ifdef LLVM_ON_WIN32
+#ifdef _WIN32
 #include "Windows/Watchdog.inc"
 #endif