dwarf2out.c (dwarf2out_define, [...]): Treat lineno 1 the same as lineno 0 before first start file directive.

	* dwarf2out.c (dwarf2out_define, dwarf2out_undef): Treat
	lineno 1 the same as lineno 0 before first start file directive.
	(optimize_macinfo_range): Likewise.

From-SVN: r187475