Further macro protection by replacing _[A-Z] with _[A-Z]p

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@145410 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/utility b/include/utility
index dd9ff33..2efea28 100644
--- a/include/utility
+++ b/include/utility
@@ -180,12 +180,12 @@
     return __first2;
 }
 
-template<class _Tp, size_t _N>
+template<class _Tp, size_t _Np>
 inline _LIBCPP_INLINE_VISIBILITY
 void
-swap(_Tp (&__a)[_N], _Tp (&__b)[_N]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value)
+swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value)
 {
-    _VSTD::swap_ranges(__a, __a + _N, __b);
+    _VSTD::swap_ranges(__a, __a + _Np, __b);
 }
 
 template <class _Tp>