* dwarf2read.c (struct attribute): Increase sizes of unsnd and snd

* dwarf2read.c (struct attribute): Increase sizes of unsnd and snd
fields to allow larger integer sizes.
(read_subrange_type): Increase size of bound values.
Add logic to determine signedness based on base-type size, signedness.
(read_attribute_value): Change format for bad byte size in message.
(read_8_bytes): Increase size of result type.
(dump_die_shallow): Change format for value.
(dwarf2_get_attr_constant_value): Increase size of return type.
Correct comment.
* gdbtypes.c (create_range_type): Change API to increase size of
bounds. struct field -> union field.
Always take signedness from base type.
(check_typedef): Use new API for TYPE_LOW_BOUND, TYPE_HIGH_BOUND.
(recursive_dump_type, copy_type_recursive): Adjust to new
representation of range types.
* gdbtypes.h (fields_or_bounds): New union containing struct field and
new struct range_bounds, used for range types.
(TYPE_RANGE_DATA): New macro to access range_bounds member.
(TYPE_LOW_BOUND, TYPE_HIGH_BOUND): Represent with new TYPE_RANGE_DATA.
(TYPE_LOW_BOUND_UNDEFINED, TYPE_HIGH_BOUND_UNDEFINED): New macros,
taking over the job of TYPE_FIELD_ARTIFICIAL for range bounds.
(SET_TYPE_LOW_BOUND, SET_TYPE_HIGH_BOUND, SET_TYPE_LOW_BOUND_DEFINED)
(SET_TYPE_HIGH_BOUND_DEFINED): New macros.
(TYPE_FIELDS, TYPE_BASECLASS, TYPE_BASECLASS_NAME, TYPE_FIELD)
(TYPE_ARRAY_UPPER_BOUND_IS_UNDEFINED)
(TYPE_ARRAY_LOWER_BOUND_IS_UNDEFINED, TYPE_ARRAY_UPPER_BOUND_VALUE)
(TYPE_ARRAY_LOWER_BOUND_VALUE):	Adjust to new representation.
(create_range_type): Adjust API.
* ada-lang.c (ada_modulus): Use new extended bound values.
(discrete_type_low_bound): Rename to...
(ada_discrete_type_low_bound): ... and make external.
(discrete_type_high_bound): Rename to...
(ada_discrete_type_high_bound): ... and make external.
(ada_value_slice_from_ptr, ada_array_bound_from_type)
(ada_evaluate_subexp, to_fixed_range_type):
Use ada_discrete_type_low_bound, ada_discrete_type_high_bound.
* ada-typeprint.c (print_range): Use ada_discrete_type_low_bound,
ada_discrete_type_high_bound.  Don't look at field count, which
is no longer meaningful.  Print bounds whenever argument is a range
or enumeration.
* ada-lang.h (ada_discrete_type_low_bound,ada_discrete_type_high_bound):
Declare.
* varobj.c (c_describe_child): Adjust to render larger values.
* mdebugread.c (parse_type): Use proper abstractions for range types:
TYPE_RANGE_DATA, SET_TYPE_LOW_BOUND_DEFINED,
SET_TYPE_HIGH_BOUND_DEFINED.
* p-typeprint.c (pascal_type_print_varspec_prefix): Use larger format
for bounds.