configure.ac: Check assembler support for R_PPC64_ENTRY relocation.

configure.ac: Check assembler support for R_PPC64_ENTRY relocation.

	* configure.ac: Check assembler support for R_PPC64_ENTRY relocation.
	* configure: Regenerate.
	* config.in: Regenerate.
	* config/rs6000/rs6000.c (rs6000_global_entry_point_needed_p): New
	function.
	(rs6000_output_function_prologue): Use it instead of checking
	cfun->machine->r2_setup_needed.  Use internal labels instead of
	GNU as local label extension.  Handle ELFv2 large code model.
	(rs6000_output_mi_thunk): Do not set cfun->machine->r2_setup_needed.
	(rs6000_elf_declare_function_name): Handle ELFv2 large code model.

From-SVN: r231202