LOG2_BY_256        92 maint/gnulib/lib/exp2.c     double z = (x * 256.0 - nm) * (LOG2_BY_256 * 0.5);
LOG2_BY_256       105 maint/gnulib/lib/exp2l.c     long double z = (x * 256.0L - nm) * (LOG2_BY_256 * 0.5L);