bfd: prevent all but undef weak syms from becoming dynamic in sparc.

bfd: prevent all but undef weak syms from becoming dynamic in sparc.

Prevent sparc backend making symbols dynamic unless they are undefined
weak. Use R_SPARC_RELATIVE for the symbols which are not dynamic in PIC.

This patch is tested on sparc64-unknown-linux-gnu, no regressions are
found.

bfd/ChangeLog:

2017-06-29  Egeyar Bagcioglu  <egeyar.bagcioglu@oracle.com>

	* elfxx-sparc.c (allocate_dynrelocs): Don't make a symbol dynamic
	unless it is undefined weak.
	* elfxx-sparc.c (_bfd_sparc_elf_relocate_section): Set the flag
	relative_reloc to direct non-dynamic symbols to R_SPARC_RELATIVE
	relocation.
	* elfxx-sparc.c (_bfd_sparc_elf_finish_dynamic_symbol): If symbol
        is not dynamic in PIC, abort.