PR 51808 Constify binding_label.

PR 51808 Constify binding_label.

2012-01-29  Janne Blomqvist  <jb@gcc.gnu.org>

	PR fortran/51808
	* decl.c (set_binding_label): Make binding_label argument const.
	(curr_binding_label): Constify.
	* gfortran.h (gfc_symbol): Constify binding_label.
	(gfc_common_head): Likewise.
	(get_iso_c_sym): Likewise.
	* match.c (gfc_match_name_C): Constify buffer argument.
	* match.h (gfc_match_name_C): Likewise.
	* resolve.c (set_name_and_label): Constify binding_label argument.
	(gfc_iso_c_sub_interface): Constify binding_label variable.
	* symbol.c (get_iso_c_sym): Constify binding_label argument.

From-SVN: r183679