diff --git a/src/fcwindows.h b/src/fcwindows.h
index 02489d9..a0eee67 100644
--- a/src/fcwindows.h
+++ b/src/fcwindows.h
@@ -32,8 +32,13 @@
 #endif
 
 #ifdef _WIN32
+   /* Request Windows Vista for building.  This is required to
+    * get MemoryBarrier on mingw32... */
+#  if defined(_WIN32_WINNT) && _WIN32_WINNT < 0x0600
+#    undef _WIN32_WINNT
+#  endif
 #  ifndef _WIN32_WINNT
-#    define _WIN32_WINNT 0x0500
+#    define _WIN32_WINNT 0x0600
 #  endif
 #  define WIN32_LEAN_AND_MEAN
 #  define WIN32_EXTRA_LEAN