* tree.h (TREE_LOCUS): Rename from DECL_SOURCE_LOCATION; make const.
	(TREE_FILENAME, TREE_LINENO): Likewise.
	(set_tree_locus, copy_tree_locus, set_tree_file_line): New.
	(TREE_LOCUS_SET_P): New.
	* c-aux-info.c, c-decl.c, c-parse.in, coverage.c, dbxout.c,
	diagnostic.c, dwarf2out.c, dwarfout.c, function.c, integrate.c,
	print-tree.c, stmt.c, toplev.c, tree-dump.c, tree-inline.c,
	tree-optimize.c, tree.c, tree.def, xcoffout.c, config/alpha/alpha.c,
	config/mips/mips.c, doc/c-tree.texi, objc/objc-act.c: Update to match.

ada/
	* trans.c, utils.c: Update for DECL_SOURCE_LOCATION rename and
	change to const.

cp/
	* class.c, cp-tree.h, decl.c, decl2.c, error.c, init.c,
	method.c, optimize.c, pt.c, semantics.c, tree.c: Update for
	DECL_SOURCE_LOCATION rename and change to const.

f/
	* com.c, ste.c: Update for DECL_SOURCE_LOCATION rename and
	change to const.

java/
	* class.c, decl.c, jcf-parse.c, jcf-write.c, parse.y,
	resource.c: Update for DECL_SOURCE_LOCATION rename and change to const.

treelang/
	* treetree.c: Update for DECL_SOURCE_LOCATION rename and
	change to const.

From-SVN: r71636