[libc++] Remove _LIBCPP_BUILDING_XXX macros, which are redundant since _LIBCPP_BUILDING_LIBRARY

Summary: As suggested by Marshall in https://reviews.llvm.org/D49914

Reviewers: mclow.lists, EricWF

Subscribers: christof, dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D50008

llvm-svn: 338475
diff --git a/libcxx/include/functional b/libcxx/include/functional
index 8026189..6b70f73 100644
--- a/libcxx/include/functional
+++ b/libcxx/include/functional
@@ -2005,7 +2005,7 @@
 
 template <int _Np> struct __ph {};
 
-#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_BIND)
+#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
 _LIBCPP_FUNC_VIS extern const __ph<1>   _1;
 _LIBCPP_FUNC_VIS extern const __ph<2>   _2;
 _LIBCPP_FUNC_VIS extern const __ph<3>   _3;
@@ -2027,7 +2027,7 @@
 /* _LIBCPP_INLINE_VAR */ constexpr __ph<8>   _8{};
 /* _LIBCPP_INLINE_VAR */ constexpr __ph<9>   _9{};
 /* _LIBCPP_INLINE_VAR */ constexpr __ph<10> _10{};
-#endif // defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_BIND)
+#endif // defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
 
 }  // placeholders