qsort: dwarf2.c

qsort: dwarf2.c

This patch ensures qsort stability in line and function sorting done
in dwarf2.c.  For the line sequences we make use of an existing field
that isn't used until later, as a monotonic counter for the qsort.

	* dwarf2.c (struct lookup_funcinfo): Add idx field.
	(compare_lookup_funcinfos): Perform final sort on idx.
	(build_lookup_funcinfo_table): Set idx.
	(compare_sequences): Perform final sort on num_lines.
	(build_line_info_table): Set num_lines and line_info_lookup earlier.
	(sort_line_sequences): Set num_lines for sort.