Don't make dynamic .data.rel.ro SEC_READONLY
    
    I'd made this dynamic section read-only so a flag test distinguished
    it from .dynbss, but like any other .data.rel.ro section it really
    should be marked read-write.  (It is read-only after relocation, not
    before.)  When using the standard linker scripts this usually doesn't
    matter since the output section is among other read-write sections and
    not page aligned.  However, it might matter in the extraordinary case
    of the dynamic section being the only .data.rel.ro section with the
    output section just happening to be page aligned and a multiple of a
    page in size.  In that case the output section would be read-only, and
    live it its own read-only PT_LOAD segment, which is incorrect.
    
    	* elflink.c (_bfd_elf_create_dynamic_sections): Don't make
    	dynamic .data.rel.ro read-only.
    	* elf32-arm.c (elf32_arm_finish_dynamic_symbol): Compare section
    	rather than section flags when deciding where copy reloc goes.
    	* elf32-cris.c (elf_cris_finish_dynamic_symbol): Likewise.
    	* elf32-hppa.c (elf32_hppa_finish_dynamic_symbol): Likewise.
    	* elf32-i386.c (elf_i386_finish_dynamic_symbol): Likewise.
    	* elf32-metag.c (elf_metag_finish_dynamic_symbol): Likewise.
    	* elf32-microblaze.c (microblaze_elf_finish_dynamic_symbol): Likewise.
    	* elf32-nios2.c (nios2_elf32_finish_dynamic_symbol): Likewise.
    	* elf32-or1k.c (or1k_elf_finish_dynamic_symbol): Likewise.
    	* elf32-ppc.c (ppc_elf_finish_dynamic_symbol): Likewise.
    	* elf32-s390.c (elf_s390_finish_dynamic_symbol): Likewise.
    	* elf32-tic6x.c (elf32_tic6x_finish_dynamic_symbol): Likewise.
    	* elf32-tilepro.c (tilepro_elf_finish_dynamic_symbol): Likewise.
    	* elf64-ppc.c (ppc64_elf_finish_dynamic_symbol): Likewise.
    	* elf64-s390.c (elf_s390_finish_dynamic_symbol): Likewise.
    	* elf64-x86-64.c (elf_x86_64_finish_dynamic_symbol): Likewise.
    	* elfnn-aarch64.c (elfNN_aarch64_finish_dynamic_symbol): Likewise.
    	* elfnn-riscv.c (riscv_elf_finish_dynamic_symbol): Likewise.
    	* elfxx-mips.c (_bfd_mips_vxworks_finish_dynamic_symbol): Likewise.
    	* elfxx-sparc.c (_bfd_sparc_elf_finish_dynamic_symbol): Likewise.
    	* elfxx-tilegx.c (tilegx_elf_finish_dynamic_symbol): Likewise.