linspace: remove use of error_state. * libinterp/corefcn/data.cc: current use of error_state is only useful for a nicer error message about N not being an integer. However, octave::idx_type_value() does not error for that, and even in that case, it must be cast to integer silently for Matlab compatibility.

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_openmp.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