* sysdeps/ieee754/ldbl2mpn.c (__mpn_extract_long_double):
Handle 80-bit denormalized numbers correct.
* stdlib/strtod.c,stdlib/strtof.c,stdlib/strtold.c:
[IMPLICIT_ONE,*_MAX_10_EXP_LOG]: not needed anymore.
* stdlib/strtod.c (RETURN): parenthesis around return value.
(round_and_return): correct handling of denormalized numbers.
(__strtod_internal): don't check for grouping when not requested
while returning 0.0.
* stdio/fpioconst.[ch]: [LDBL_MAX_10_EXP_LOG]: don't use it.
LAST_POW10 defines the maximal available exponent.
* stdlib/{atof,atoi,atol}.c: use __strtoX_internal.
