re PR debug/26881 (internal compiler error in dwarf2out_finish)

re PR debug/26881 (internal compiler error in dwarf2out_finish)

	PR debug/26881
	* cgraph.c: Fix comments.
	(cgraph_varpool_mark_needed_node): Mark only variables not already
	output to file.
	* cgraphunit.c: Update comments; include gt-cgraphunit.h
	(cgraph_varpool_assembled_nodes_queue): New static variable.
	(cgraph_varpool_assemble_decl): Record output decls for debug out code.
	(cgraph_varpool_output_debug_info): New function.
	(cgraph_finalize_compilation_unit, cgraph_optimize): Call it.
	* Makefile.in: Add gt-cgraphunit.h
	* gcc.dg/debug/pr26881.c: New file.

From-SVN: r116374