dtoastr,ftoastr,ldtoastr: port to c-strtod changes Decouple these modules from c-strtod. Nowadays it’s reasonable to assume the C99 signatures for strtod and strtold. Programs that require stricter adherence to C99 should also use the strtod and strtold modules as needed, and we no longer need the HAVE_C99_STRTOLD macro. * NEWS: Mention this. * lib/ftoastr.c (STRTOF) [LENGTH == 3]: Assume strtold. * m4/c-strtod.m4 (gl_C_STRTOLD): Do not define HAVE_C99_STRTOLD. * modules/dtoastr, modules/ftoastr, modules/ldtoastr: (Files): Remove m4/c-strtod.m4. (configure.ac): Do not require gl_C99_STRTOLD, which no longer exists.