diff --git a/include/Config/unistd.h b/include/Config/unistd.h
index 5b621a6b762..e9ca783e83d 100644
--- a/include/Config/unistd.h
+++ b/include/Config/unistd.h
@@ -20,4 +20,8 @@
 #include <unistd.h>
 #endif
 
+#ifdef _WIN32
+#include <process.h>
+#endif
+
 #endif
diff --git a/include/llvm/Config/unistd.h b/include/llvm/Config/unistd.h
index 5b621a6b762..e9ca783e83d 100644
--- a/include/llvm/Config/unistd.h
+++ b/include/llvm/Config/unistd.h
@@ -20,4 +20,8 @@
 #include <unistd.h>
 #endif
 
+#ifdef _WIN32
+#include <process.h>
+#endif
+
 #endif