generate a new section if the SHF_GNU_RETAIN bit doesn't match.
* config/obj-elf.c (SEC_ASSEMBLER_SHF_MASK): New.
(get_section_by_match): Also check if SEC_ASSEMBLER_SHF_MASK of
sh_flags matches. Rename info to sh_info.
(obj_elf_change_section): Don't check previous SHF_GNU_RETAIN.
Rename info to sh_info.
(obj_elf_section): Rename info to sh_info. Set sh_flags for
SHF_GNU_RETAIN.
* config/obj-elf.h (elf_section_match): Rename info to sh_info.
Add sh_flags.
* testsuite/gas/elf/elf.exp: Run section27.
* testsuite/gas/elf/section24b.d: Updated.
* testsuite/gas/elf/section27.d: New file.
* testsuite/gas/elf/section27.s: Likewise.