diff --git a/llvm/lib/Support/Process.cpp b/llvm/lib/Support/Process.cpp
index 1c8cc6e..d5f9bde 100644
--- a/llvm/lib/Support/Process.cpp
+++ b/llvm/lib/Support/Process.cpp
@@ -93,6 +93,6 @@
 #ifdef LLVM_ON_UNIX
 #include "Unix/Process.inc"
 #endif
-#ifdef LLVM_ON_WIN32
+#ifdef _WIN32
 #include "Windows/Process.inc"
 #endif