* final.c (SEEN_BB, SEEN_NOTE, SEEN_EMITTED): Define.
	(final_scan_insn): Update to take an additional SEEN argument.  Emit
	a line note after the prologue.  Make static.
	(line_note_exists): Remove.
	(final): Don't initialize line_note_exists.  Update call to
	final_scan_insn.
	* output.h (final_scan_insn): Remove prologue.
	* function.c (set_insn_locators): Update comment.
	(thread_prologue_and_epilogue_insns): Add a comment.

From-SVN: r76060