rectint: fix for non-overlapping rectangle, and support ND boxes (bug #44904) * scripts/geometry/rectint.m: it was giving incorrect results (not zero) when the coordinates for X overlapped but the Y did not (added tests for this bug). This is a complete rewrite of the function. The new version performs approximately 1000 times faster and adds supports N dimensional boxes in which case it measures the volume or hypervolume of the hypervolume intersections. * NEWS: make note that rectint() now supports ND.

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