[libc++] Fix preprocessor guard for overload declaration

Fix a typo in the conditional.  Caught by going through list of removed
symbols when building with hidden visibility.

Differential Revision: https://reviews.llvm.org/D26825

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@287309 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/new b/include/new
index 96e5b8e..6b432f2 100644
--- a/include/new
+++ b/include/new
@@ -180,7 +180,7 @@
 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz, const std::nothrow_t&) _NOEXCEPT _NOALIAS;
 _LIBCPP_OVERRIDABLE_FUNC_VIS void  operator delete[](void* __p) _NOEXCEPT;
 _LIBCPP_OVERRIDABLE_FUNC_VIS void  operator delete[](void* __p, const std::nothrow_t&) _NOEXCEPT;
-#ifdef _LIBCPP_HAS_NO_SIZED_DEALLOCATION
+#ifndef _LIBCPP_HAS_NO_SIZED_DEALLOCATION
 _LIBCPP_OVERRIDABLE_FUNC_VIS void  operator delete[](void* __p, std::size_t __sz) _NOEXCEPT;
 #endif