diff --git a/configure.ac b/configure.ac
index 16f14cbc61..acf253eadc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -5382,7 +5382,7 @@ else
     AC_LANG_PROGRAM([[
       #include <windows.h>
     ]],[[
-      #if _WIN32_WINNT < 0x600
+      #if (_WIN32_WINNT < 0x600)
       #error
       #endif
     ]])