fix: toolchain build reproducibility — header ordering, libcody, specs, GNU-stack

fix: toolchain build reproducibility — header ordering, libcody, specs, GNU-stack

- Move AdrOS sysroot headers installation to AFTER Newlib install so
  Newlib's make install doesn't overwrite our custom sys/dirent.h
  (fixes DIR unknown type error on first build)
- Move Newlib header patching (sys/stat.h, sys/signal.h, sys/wait.h,
  glob.h) to after Newlib install (fixes sed on non-existent files)
- Keep libcody in GCC host_libs — required by cc1plus (C++ frontend)
- Add all-libcody to step 4 make targets
- Move specs file creation to after step 4 (GCC full install overwrites it)
- Add .note.GNU-stack to crti-adros.S (fixes executable stack warning)
- Fix *.h glob in libgloss/adros cp (no .h files exist)
- Add toolchain/build/ and toolchain/logs/ to .gitignore
- Update README.md: clarify patches/ are reference diffs, add native-toolchain.patch