libdfp: Fix NOT_in_libdfp for cxx tests
libdpf: Remove legacy Makefile support for GLIBC

Libdfp does not support for some time to being built as a GLIBC addon.
This patch remove the legacy Makefile rules for glibc_headers and
glibc_builddir.
libdfp: Fix logbd[32|64]128] return for negative infinity

This patch makes logd function to return a positive infinity for both
positive and negative infinities.
libdfp: Add FP_LLOGB0 and FP_LLOGBNAN return codes

This patch add the two definitions if they are not already defined in
system libraries. It also change llogb to return FP_LLOGB0 in case of 0
input and FP_LLOGBNAN in case of NaN.
libdfp: Add fpclassifyd[32|64|128] prototypes

This patch adds the missing fpclassifyd[32|64|128] to libdfp math
include.
libdfp: Add entry point for shared-libraries

This patch adds a entry point function to print useful information
when the libdfp shared library is called directly.
libdfp: Add HUGE_VAL_D32 and HUGE_VAL_D128

This patch add the missing HUGE_VAL_D32 and HUGE_VAL_D128 values on
libdfp math.h header.
libdfp: New framework for tests

This patch adds a new framework to create tests for libdfp. Instead of
static code C tests the new framework uses descriptive files with input
and expected output. It will be processed by a script that will actually
generate code.

A example test description is as follow:

  # name quantum
  # arg1 decimal
  # ret  decimal

  Inf                    Inf
  -Inf                   Inf
  NaN                    NaN
  sNaN                   sNaN

  DEC_MAX                1E+DEC_MAX_EXP
  DEC_MIN                1E-DEC_MIN_EXP
  DEC_SUBNORMAL_MIN      1E-DEC_MIN_EXP_SUB

  -DEC_MAX               1E+DEC_MAX_EXP
  -DEC_MIN               1E-DEC_MIN_EXP
  -DEC_SUBNORMAL_MIN     1E-DEC_MIN_EXP_SUB

Initial lines describe the function (in the case quantum that has one
_Decimal as argument and return a _Decimal). Each line following
descriptions will be translated to a function call and its return will
be checked against expected value.

The 'decimal' directive will use a _Decimal type according to script
input argument. This makes the test description file independent of the
decimal type. Some directives will be set in accord of decimal type,
like DEC_MAX to DEC32_MAX for _Decimal32.

Some tests should be run only for certain decimal types. To do so, the
directive decimalN can be used as:

  20.971525              0.000001               decimal64 decimal128

The test will run only for _Decimal64 and _Decimal128.
libdfp: Adapt samequantum test to new framework
libdfp: Adapt logb test to new framework
libdfp: Adapt llquantexp test to new framework
libdfp: Adapt isnan/isinf/isfinite to new test framework
libdfp: Adapt issignaling test to new test framework
libdfp: Adapt ilogb/llogb tests to new framework
libdfp: Adapt quantum test to new test framework
libdpf: Adapt rounding tests to new framework

This patch adapt ceil, floor, nearbyint, round, roundeven, and trunc
test to new test framework.
libdfp: Adapt fpclassify to new test framework
libdfp: Adapt quantize test to new framework
libdfp: Remove unnecessary tests

This patch remove test-GCC-PR52140, test-negate, test-param.c
(all covered by GCC), and test-stdlib.c (not really necessary).
libdfp: Name change for test-round.c

This patch changes the name of test-round.c to test-fenv.c (showing
it is indeed testing rounding related to fenv) and add some minor
cleaups in the code.