improve accuracy of range/scalar arithmetic (bug #42589) * Range.h, Range.cc (Range::Range (double, double, double, octave_idx_type): New protected constructor. (operator -, operator +, operator *): Use new constructor. (Range::Range (double, double, octave_idx_type): Also check that the limit remains finite.

EXTRA_DIST += \
  m4/module.mk \
  m4/ax_blas.m4 \
  m4/ax_blas_f77_func.m4 \
  m4/ax_compare_version.m4 \
  m4/ax_lapack.m4 \
  m4/ax_pthread.m4 \
  m4/gnulib-cache.m4 \
  m4/libtool.m4 \
  m4/ltoptions.m4 \
  m4/ltsugar.m4 \
  m4/ltversion.m4 \
  m4/lt~obsolete.m4 \
  m4/pkg.m4