* reloc.c (BFD_RELOC_RL78_CODE): Add.
* libbfd.h: Regenerate.
* bfd-in2.h: Regenerate.
* elf32-rl78.c (rl78_elf_relocate_section): Handle weak code
references in compuated relocs.

* config/tc-rl78.c (reloc_function): Add %code -> BFD_RELOC_RL78_CODE.
(rl78_op): Handle %code().
(rl78_cons_fix_new): Likewise, but ignore for 20-bit operands.
(tc_gen_reloc): Likwise; convert to a computed reloc.
(md_apply_fix): Likewise.