PR 6443

	PR 6443
	* elf32-ppc.c (MUST_BE_DYN_RELOC): Delete.
	(must_be_dyn_reloc): New function.
	(ppc_elf_check_relocs): Don't set DF_STATIC_TLS for tprel relocs
	in pies.
	(ppc_elf_tls_optimize): Optimise pies.
	(ppc_elf_relocate_section): Use a section symbol rather than no
	symbol if possible for LD->IE TLS sequence, but don't error if
	we must use no symbol.
	* elf64-ppc.c (MUST_BE_DYN_RELOC): As for elf32-ppc.c.
	(must_be_dyn_reloc): Likewise.
	(ppc64_elf_check_relocs): Likewise.
	(ppc64_elf_tls_optimize): Likewise.
	(ppc64_elf_relocate_section): Likewise.