lookfor.m: Overhaul function and fix bug #44924. * lookfor.m: Rewrite docstring. Match variable names in function prototype to docstring. Use more meaningful variable names throughout function. Don't continue to process a function if get_first_help_sentence returns an error (bug #44924). Iterate directly over cell list rather than using a for loop with a range to index into cell list.

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