X86-64: Allow copy relocs for building PIE

X86-64: Allow copy relocs for building PIE

This patch allows copy relocs for non-GOT pc-relative relocation in PIE.

bfd/

	* elf64-x86-64.c (elf_x86_64_create_dynamic_sections): Always
	allow copy relocs for building executables.
	(elf_x86_64_check_relocs): Allow copy relocs for non-GOT
	pc-relative relocation in shared object.
	(elf_x86_64_adjust_dynamic_symbol): Allocate copy relocs for
	PIE.
	(elf_x86_64_relocate_section): Don't copy a pc-relative
	relocation into the output file if the symbol needs copy reloc.

ld/testsuite/

	* ld-x86-64/copyreloc-lib.c: New file.
	* ld-x86-64/copyreloc-main.c: Likewise.
	* ld-x86-64/copyreloc-main.out: Likewise.
	* ld-x86-64/copyreloc-main1.rd: Likewise.
	* ld-x86-64/copyreloc-main2.rd: Likewise.

	* ld-x86-64/x86-64.exp: Run copyreloc tests.