PowerPC64 treatment of absolute symbols

PowerPC64 treatment of absolute symbols

Supporting -static-pie on PowerPC64 requires the linker to properly
treat SHN_ABS symbols for cases like glibc's _nl_current_LC_CTYPE_used
absolute symbol.  I've been slow to fix the linker on powerpc because
there is some chance that this will break some shared libraries or
PIEs.

bfd/
	* elf64-ppc.c (ppc64_elf_check_relocs): Consolidate local sym
	handling code.  Don't count dyn relocs against non-dynamic
	absolute symbols.
	(dec_dynrel_count): Adjust to suit.
	(ppc64_elf_edit_toc): Don't remove entries for absolute symbols
	when pic.
	(allocate_got): Don't allocate space for got relocs against
	non-dynamic absolute syms.
	(ppc64_elf_layout_multitoc): Likewise.
	(got_and_plt_relr): Likewise.
	(ppc64_elf_size_dynamic_sections): Likewise for local got.
	(got_and_plt_relr_for_local_syms): Likewise.
	(ppc64_elf_size_stubs): Don't allocate space for relr either.
	(ppc64_elf_relocate_section): Don't write relocs against non-dynamic
	absolute symbols.  Don't optimise got and toc code sequences
	loading absolute symbol entries.
ld/
	* testsuite/ld-powerpc/abs-reloc.s,
	* testsuite/ld-powerpc/abs-static.d,
	* testsuite/ld-powerpc/abs-static.r,
	* testsuite/ld-powerpc/abs-pie.d,
	* testsuite/ld-powerpc/abs-pie.r,
	* testsuite/ld-powerpc/abs-shared.d,
	* testsuite/ld-powerpc/abs-shared.r,
	* testsuite/ld-powerpc/abs-pie-relr.d,
	* testsuite/ld-powerpc/abs-pie-relr.r,
	* testsuite/ld-powerpc/abs-shared-relr.d,
	* testsuite/ld-powerpc/abs-shared-relr.r: New tests.
	* testsuite/ld-powerpc/powerpc.exp: Run them.