elf_backend_modify_headers

elf_backend_modify_headers

This patch renames elf_backend_modify_program_headers and moves the
elf.c code tweaking the ELF file header for -pie -Ttext-segment to a
new function, _bfd_elf_modify_headers, which then becomes the default
elf_backed_modify_headers and is called from any other target
elf_backed_modify_headers.

	* elf-bfd.h (struct elf_backend_data <elf_backend_modify_headers>):
	Rename from elf_backend_modify_program_headers.
	(_bfd_elf_modify_headers): Declare.
	* elf.c (assign_file_positions_except_relocs): Set
	elf_program_header_size.  Always call elf_backend_modify_headers.
	Extract code modifying file header..
	(_bfd_elf_modify_headers): ..to here.  New function.
	* elf32-arm.c (elf_backend_modify_headers): Renamed from
	elf_backend_modify_program_headers.
	* elf32-i386.c: Similarly.
	* elf64-x86-64.c: Similarly.
	* elfxx-target.h: Similarly.  Default elf_backend_modify_headers
	to _bfd_elf_modify_headers.
	* elf-nacl.h (nacl_modify_headers): Rename from
	nacl_modify_program_headers.
	* elf-nacl.c (nacl_modify_headers): Rename from
	nacl_modify_program_headers and call _bfd_elf_modify_headers.
	* elf32-rx.c (elf32_rx_modify_headers): Similarly.
	* elf32-spu.c (spu_elf_modify_headers): Similarly.
	* elfnn-ia64.c (elfNN_ia64_modify_headers): Similarly.
	* elf32-sh.c (elf_backend_modify_program_headers): Don't undef.