or download this
sh Configure -des -Duse64bitall -Dprefix=/home/sisyphus/perl-5.33.2-d
+-Uversiononly -Dusedevel -Dd_Gconvert='sprintf((b),"%.*g",(n),(x))' &
+& make
.....
...
0.299999999999999988897769753748434595763683319091796875
sisyphus@sisyphus5-desktop:~/comp/perl-5.33.2$ ./perl -I./lib -le 'pri
+ntf "%.254g\n", 1.7e+251;'
1700000000000000056638039423376108468948472250210191793353461791741809
+721595401553113821670191901996837100770654163405637701161634938299172
+691569638797131996693245937962742921605027934132599151410492365393458
+53734303029546817799537579060533492478640128