PR 3136 * config/obj-elf.c (elf_pseudo_table): Add entry for .bss. (obj_elf_bss): New function. Change to the .bss section. Support an optional subsection number. (obj_elf_change_section): Call obj_elf_section_change_hook. (obj_elf_section): Likewise. (obj_elf_data): Likewise. (obj_elf_text): Likewise. (obj_elf_struct): Likewise. (obj_elf_subsection): Likewise. (obj_elf_previous): Likewise. * config/obj-elf.h (obj_elf_bss): Prototype. * doc/as.texi (Bss): New node.