Build-break in libstdc++-v3 at r14-1442-ge1240bda3e0bb1 for non-float128 targets

[Hans-Peter Nilsson <hp@axis.com>]

Since I don't see a quick fix at r14-1444-g3f4853a5f00fab, I
thought I'd better notify the author (I have written authors
if there was more than one ;-) of suspect commits in the
range r14-1425-g80ee7d02e8db48..e1240bda3e0b for the
build-break at r14-1442-ge1240bda3e0bb1 for cris-elf, where
I get:

/x/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc:1330:47: error: '_Float128' is not supported on this target
 1330 | from_chars(const char* first, const char* last, _Float128& value,
      |                                               ^
/x/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc:1330:49: error: expected identifier before '_Float128'
 1330 | from_chars(const char* first, const char* last, _Float128& value,
      |                                                 ^~~~~~~~~
/x/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc:1330:49: error: '_Float128' is not supported on this target
/x/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc:1330:49: error: expected ',' or '...' before '_Float128'
/x/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc: In function 'std::from_chars_result std::from_chars(const char*, const char*, int)':
/x/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc:1340:53: error: 'fmt' was not declared in this scope; did you mean 'fma'?
 1340 |   auto res = std::from_chars(first, last, ldbl_val, fmt);
      |                                                     ^~~
      |                                                     fma
/x/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc:1342:5: error: 'value' was not declared in this scope
 1342 |     value = ldbl_val;
      |     ^~~~~
make[5]: *** [Makefile:587: floating_from_chars.lo] Error 1

brgds, H-P