Convert PLT reloc only if pointer equality isn't needed

Convert PLT reloc only if pointer equality isn't needed

When pointer equality needed, we can't replace PLT relocations with
GOT relocations for -z now.  This patch checks if pointer equality is
needed before converting PLT relocations to GOT relocations.

bfd/

	PR binutils/18458
	* elf32-i386.c (elf_i386_check_relocs): Create .plt.got section
	for now binding only if pointer equality isn't needed.
	(elf_i386_allocate_dynrelocs): Use .plt.got section for now
	binding only if pointer equality isn't needed.
	* elf64-x86-64.c (elf_x86_64_check_relocs): Create .plt.got
	section for now binding only if pointer equality isn't needed.
	(elf_x86_64_allocate_dynrelocs): Use .plt.got section for now
	binding only if pointer equality isn't needed.

ld/testsuite/

	PR binutils/18458
	* ld-elf/shared.exp (build_tests): Build libpr18458a.so and
	libpr18458b.so.
	(run_tests): Run pr18458 test.
	* ld-elf/pr18458a.c: New file.
	* ld-elf/pr18458b.c: Likewise.
	* ld-elf/pr18458c.c: Likewise.