Remove constexpr support for std::apply because it introduces regressions.

llvm-svn: 235274
diff --git a/libcxx/include/__functional_base b/libcxx/include/__functional_base
index 64bc931..09424bc 100644
--- a/libcxx/include/__functional_base
+++ b/libcxx/include/__functional_base
@@ -364,7 +364,7 @@
 
 template <class _Fp, class _A0, class ..._Args,
             class>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+inline _LIBCPP_INLINE_VISIBILITY
 auto
 __invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
     -> decltype((_VSTD::forward<_A0>(__a0).*__f)(_VSTD::forward<_Args>(__args)...))
@@ -374,7 +374,7 @@
 
 template <class _Fp, class _A0, class ..._Args,
             class>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+inline _LIBCPP_INLINE_VISIBILITY
 auto
 __invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
     -> decltype(((*_VSTD::forward<_A0>(__a0)).*__f)(_VSTD::forward<_Args>(__args)...))
@@ -386,7 +386,7 @@
 
 template <class _Fp, class _A0,
             class>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+inline _LIBCPP_INLINE_VISIBILITY
 auto
 __invoke(_Fp&& __f, _A0&& __a0)
     -> decltype(_VSTD::forward<_A0>(__a0).*__f)
@@ -396,7 +396,7 @@
 
 template <class _Fp, class _A0,
             class>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+inline _LIBCPP_INLINE_VISIBILITY
 auto
 __invoke(_Fp&& __f, _A0&& __a0)
     -> decltype((*_VSTD::forward<_A0>(__a0)).*__f)
@@ -407,7 +407,7 @@
 // bullet 5
 
 template <class _Fp, class ..._Args>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+inline _LIBCPP_INLINE_VISIBILITY
 auto
 __invoke(_Fp&& __f, _Args&& ...__args)
     -> decltype(_VSTD::forward<_Fp>(__f)(_VSTD::forward<_Args>(__args)...))