* ldlang.h (lang_output_section_find): Define.

	* ldlang.h (lang_output_section_find): Define.
	(lang_output_section_statement_lookup): Update prototype.
	* ldlang.c (lang_output_section_find,
	lang_output_section_statement_lookup_1): Merge into..
	(lang_output_section_statement_lookup): ..here.  Update all callers.
	(process_insert_statements): Set constraint negative
	for output section statements we might be inserting.  Make error
	fatal on not finding insertion section.
	(lang_output_section_find): Rather than comparing
	output_section_statement.constraint against -1, test whether
	it is postive.
	(lang_output_section_statement_lookup_1): Likewise.
	(output_prev_sec_find, strip_excluded_output_sections): Likewise.
	(lang_record_phdrs): Likewise.
	* emultempl/elf32.em (output_rel_find): Likewise.
	* NEWS: Mention INSERT.