Fix PR ld/3290 regression for cross-files DW_FORM_ref_addr relocations.
* elflink.c (elf_link_add_object_symbols): Make debug symbols local
now only for non-RELOCATABLE targets.
ld/testsuite/
* ld-x86-64/dwarfreloc.exp, ld-x86-64/dwarfreloc.rd,
ld-x86-64/dwarfreloc1.s, ld-x86-64/dwarfreloc2.s: New test.
Jan Kratochvil