Пакет librep-devel: Информация

- Assume downwards stack direction for loongarch64 and riscv64
  (fixes FTBFS on those architectures).
- Don't build on armh (broken now).

- E2K: fixed build (lcc is __not__ gcc though!).
- Replaced %_target_platform with %_configure_platform
  to fix e2k build on e2kv4 machine (imz@ knows more).
- Minor spec cleanup.

- Add "aarch64" to the set of known arches (in order to make the
  stack direction autodetection work).