Thanks Sebastian\!

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@115612 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/__config b/include/__config
index 7cc07fa..d8b0a99 100644
--- a/include/__config
+++ b/include/__config
@@ -249,7 +249,7 @@
 #define constexpr const
 #endif
 
-#ifndef __has_feature(__x)
+#ifndef __has_feature
 #define __has_feature(__x) 0
 #endif