[libc++] P1645 constexpr for <numeric>

Implements P1645: constexpr for <numeric> algorithms

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D90569

GitOrigin-RevId: 67c88e47bdba2578150a9034a717d6ddcace4e13
diff --git a/include/version b/include/version
index 58f6765..2f1fd92 100644
--- a/include/version
+++ b/include/version
@@ -48,6 +48,7 @@
 __cpp_lib_constexpr_dynamic_alloc                       201907L <memory>
 __cpp_lib_constexpr_misc                                201811L <array> <functional> <iterator>
                                                                 <string_view> <tuple> <utility>
+__cpp_lib_constexpr_numeric                             201911L <numeric>
 __cpp_lib_constexpr_swap_algorithms                     201806L <algorithm>
 __cpp_lib_constexpr_utility                             201811L <utility>
 __cpp_lib_destroying_delete                             201806L <new>
@@ -254,6 +255,7 @@
 // # define __cpp_lib_concepts                             201806L
 # define __cpp_lib_constexpr_dynamic_alloc              201907L
 // # define __cpp_lib_constexpr_misc                       201811L
+# define __cpp_lib_constexpr_numeric                    201911L
 // # define __cpp_lib_constexpr_swap_algorithms            201806L
 # define __cpp_lib_constexpr_utility                    201811L
 # if _LIBCPP_STD_VER > 17 && defined(__cpp_impl_destroying_delete) && __cpp_impl_destroying_delete >= 201806L