re PR c/41049 (conversion from integer to decimal float loses trailing zeros)

gcc/
	PR c/41049
	* real.c decimal_from_integer, decimal_integer_string): New.
	(real_from_integer): Use them as special case for decimal float.
	* config/dfp-bit.c (_si_to_sd, _usi_to_sd): Use default rounding.
	(_di_to_sd, _di_to_dd, _di_to_td, _udi_to_sd, _udi_to_dd, _udi_to_td):
	Do not append zero after the decimal point in string to convert.
gcc/testsuite/
	PR c/41049
	* dfp/pr41049.c: New test.

From-SVN: r151806