diff --git a/src/hb-atomic-private.hh b/src/hb-atomic-private.hh
index b909bc8ef..c7456e090 100644
--- a/src/hb-atomic-private.hh
+++ b/src/hb-atomic-private.hh
@@ -42,7 +42,7 @@
 #if 0
 
 
-#elif !defined(HB_NO_MT) && defined(_MSC_VER) || defined(__MINGW32__)
+#elif !defined(HB_NO_MT) && (defined(_MSC_VER) || defined(__MINGW32__))
 
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
diff --git a/src/hb-mutex-private.hh b/src/hb-mutex-private.hh
index 5b3a17e91..fcbdb31b7 100644
--- a/src/hb-mutex-private.hh
+++ b/src/hb-mutex-private.hh
@@ -42,7 +42,7 @@
 #if 0
 
 
-#elif !defined(HB_NO_MT) && defined(_MSC_VER) || defined(__MINGW32__)
+#elif !defined(HB_NO_MT) && (defined(_MSC_VER) || defined(__MINGW32__))
 
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>