Add Char support in INT_SIGN_MAP closure

[TApplencourt]

Itt does

typedef unsigned char __itt_pt_region;
__itt_pt_region __itt_pt_region_create(const char *name);

It was leading to

/home/applenco/project/p25.07/THAPI/utils/yaml_ast_lttng.rb:10:in `lttng_type': Unsupported type __itt_pt_region! (RuntimeError)
        from /home/applenco/project/p25.07/THAPI/utils/yaml_ast_lttng.rb:142:in `lttng_type'
        from /home/applenco/project/p25.07/THAPI/utils/gen_babeltrace_model_helper.rb:167:in `get_fields_types_name'
        from /home/applenco/project/p25.07/THAPI/utils/gen_babeltrace_model_helper.rb:186:in `gen_event_fields_bt_model'
        from /home/applenco/project/p25.07/THAPI/utils/gen_babeltrace_model_helper.rb:207:in `gen_event_bt_model'
        from ../../../backends/ze/gen_babeltrace_ze_model.rb:13:in `block (2 levels) in <main>'
        from ../../../backends/ze/gen_babeltrace_ze_model.rb:11:in `collect'
        from ../../../backends/ze/gen_babeltrace_ze_model.rb:11:in `block in <main>'
        from ../../../backends/ze/gen_babeltrace_ze_model.rb:10:in `collect'
        from ../../../backends/ze/gen_babeltrace_ze_model.rb:10:in `<main>'
make: *** [Makefile:1716: btx_ze_model.yaml] Error 1
make: *** Deleting file 'btx_ze_model.yaml'

The fix make this pass.

I did make a test adding

typedef unsigned char __itt_pt_region;
void __itt_pt_region_create(__itt_pt_region name);

It did generate

TRACEPOINT_EVENT(
  lttng_ust_ze,
  __itt_pt_region_create_entry,
  TP_ARGS(
    __itt_pt_region, name
  ),
  TP_FIELDS(
    ctf_integer(__itt_pt_region, name, name)
  )
)

Who look good. The btx_ze_model look also correct

  - :name: lttng_ust_ze:__itt_pt_region_create_entry
    :payload_field_class:
      :type: structure
      :members:
      - :name: name
        :field_class:
          :cast_type: __itt_pt_region
          :type: integer_unsigned
          :field_value_range: 8

(The failure in the ITT branch are I suppose by another change then :D )

[Kerilk]

Looking good from here.

[TApplencourt]

Thanks for the quick review!