[gn build] Port a06591b

Author: llvmgnsyncbot

llvm/utils/gn/secondary/libcxx/include/BUILD.gn

@@ -859,6 +859,7 @@ if (current_toolchain == default_toolchain) {
       "__type_traits/is_floating_point.h",
       "__type_traits/is_function.h",
       "__type_traits/is_fundamental.h",
+      "__type_traits/is_implicit_lifetime.h",
       "__type_traits/is_implicitly_default_constructible.h",
       "__type_traits/is_integral.h",
       "__type_traits/is_literal_type.h",