* automake.in (variable_conditions): Split into ...

* automake.in (variable_conditions): Split into ...
(variable_conditions, variable_sorted_conditions): ... these
functions, where variable_sorted_conditions has the semantic of
the old variable_condition.
(target_conditions): New function.
(msg_var, handle_lib_objects_cond, check_ambiguous_conditional,
variable_not_always_defined_in_cond, macro_define,
variable_defined, check_variable_defined_unconditionally,
variable_conditions_recursive_sub,
variable_conditions_permutations, variable_value_as_list,
variable_value_as_list_recursive_worker, append_exeext,
am_install_var, require_variables_for_macro): Use variable_conditions.
(msg_target, rule_define): Use target_conditions.
(define_objects_from_sources, macro_define, macro_dump,
variable_pretty_output): Use variable_sorted_conditions.