diff --git a/mingw-w64-headers-sigset_t.patch b/mingw-w64-headers-sigset_t.patch
index 5ee9213..3b043c0 100644
--- a/mingw-w64-headers-sigset_t.patch
+++ b/mingw-w64-headers-sigset_t.patch
@@ -12,7 +12,7 @@
 +#endif
  
 -#ifndef _NO_OLDNAMES
-+#ifndef _POSIX
++#ifdef _POSIX
  typedef _sigset_t	sigset_t;
  #endif
  #endif	/* Not _SIGSET_T_ */