Merge branch 'refactor/remove-unused-nightly' into 'master'

lib: remove unused Nightly features

See merge request redox-os/relibc!713

src/lib.rs

@@ -16,17 +16,14 @@
 #![feature(asm_const)]
 #![feature(c_variadic)]
 #![feature(core_intrinsics)]
-#![feature(int_roundings)]
 #![feature(maybe_uninit_slice)]
 #![feature(lang_items)]
 #![feature(let_chains)]
 #![feature(linkage)]
-#![feature(naked_functions)]
 #![feature(pointer_is_aligned_to)]
 #![feature(ptr_as_uninit)]
 #![feature(slice_as_chunks)]
 #![feature(stmt_expr_attributes)]
-#![feature(str_internals)]
 #![feature(strict_provenance)]
 #![feature(sync_unsafe_cell)]
 #![feature(thread_local)]