Sync include, libiberty with GCC.

Sync include, libiberty with GCC.

include:
2020-09-10  Felix Willgerodt  <felix.willgerodt@intel.com>

    Sync with GCC
    2020-08-17  Felix Willgerodt  <felix.willgerodt@intel.com>

    * floatformat.h (floatformat_bfloat16_big): New.
    (floatformat_bfloat16_little): New.

libiberty:
2020-09-10  Felix Willgerodt  <felix.willgerodt@intel.com>

    Sync with GCC
    2020-08-17  Felix Willgerodt  <felix.willgerodt@intel.com>

    * floatformat.c (floatformat_bfloat16_big): New.
    (floatformat_bfloat16_little): New.