gdb/

gdb/
	Code cleanup.
	* dwarf2-frame.c (dwarf2_frame_ctx_funcs): New.
	(execute_stack_op): Use dwarf2_frame_ctx_funcs
	* dwarf2expr.c (dwarf_get_base_type): Access get_base_type via funcs.
	(execute_stack_op): Access read_reg, get_frame_base, read_mem,
	get_frame_cfa, get_tls_address and dwarf_call via funcs.
	* dwarf2expr.h (struct dwarf_expr_context): New forward declaration.
	(struct dwarf_expr_context_funcs): New, move here methods from ...
	(struct dwarf_expr_context): ... here.  New fields funcs.
	* dwarf2loc.c (dwarf_expr_dwarf_call): Access get_frame_pc via funcs.
	(dwarf_expr_ctx_funcs): New.
	(dwarf2_evaluate_loc_desc_full): Use dwarf_expr_ctx_funcs.
	(needs_frame_dwarf_call): Access get_frame_pc via funcs.
	(needs_frame_ctx_funcs): New.
	(dwarf2_loc_desc_needs_frame): Use needs_frame_ctx_funcs.