Enable required features for core::array in libstd

Author: nvzqz

src/libstd/lib.rs

@@ -243,6 +243,7 @@
 #![feature(allow_internal_unsafe)]
 #![feature(allow_internal_unstable)]
 #![feature(align_offset)]
+#![feature(array_error_internals)]
 #![feature(asm)]
 #![feature(box_syntax)]
 #![feature(cfg_target_has_atomic)]
@@ -257,6 +258,7 @@
 #![feature(core_intrinsics)]
 #![feature(dropck_eyepatch)]
 #![feature(exact_size_is_empty)]
+#![feature(fixed_size_array)]
 #![feature(float_from_str_radix)]
 #![feature(fn_traits)]
 #![feature(fnbox)]