Enable -Bsymbolic and -Bsymbolic-functions to PIE

Enable -Bsymbolic and -Bsymbolic-functions to PIE

Before binutils 2.26, -Bsymbolic and -Bsymbolic-functions were also
applied to PIE so that "ld -pie -Bsymbolic -E" can be used to export
symbols in PIE with local binding.  This patch re-enables -Bsymbolic
and -Bsymbolic-functions for PIE.

	PR ld/19615
	* ld.texinfo: Document -Bsymbolic and -Bsymbolic-functions for
	PIE.
	* lexsup.c (parse_args): Enable -Bsymbolic and
	-Bsymbolic-functions for PIE.
	* testsuite/ld-i386/i386.exp: Run pr19175.
	* testsuite/ld-i386/pr19615.d: New file.
	* testsuite/ld-i386/pr19615.s: Likewise.
	* testsuite/ld-x86-64/pr19615.d: Likewise.
	* testsuite/ld-x86-64/pr19615.s: Likewise.