RFA: Various enhancements to the fixed-point support implementation

[Joel Brobecker]

Hello,

The following patch series implements the suggestions Simon made
in reviewing the first patch series, which I felt deserved to be
their own patch. I think it allows us to review those changes
independently of the first implementation (which Simon said was
find to push).

  - [RFA 1/6] change gmp_string_asprintf to return an std::string
  - [RFA 2/6] gmp-utils: Convert the read/write methods to using
  - [RFA 3/6] gdbtypes.h: Get rid of the TYPE_FIXED_POINT_INFO macro
  - [RFA 4/6] Make fixed_point_type_base_type a method of struct type
  - [RFA 5/6] Make function fixed_point_scaling_factor a method of struct
  - [RFA 6/6] valarith.c: Replace INIT_VAL_WITH_FIXED_POINT_VAL macro by

The patches were tested on x86_64-linux.

Thank you!
-- 
Joel