Clean up questionable code bits identified by clang sanitize. * data.cc (Fnorm): in %!test, don't test with a single value which exceeds range of single. * find.cc (find_nonzero_elem_idx): Remove unused variable assignment to n_to_find. * load-save.cc (Fsave): Declare argc just before usage. * ls-hdf5.cc (hdf5_read_next_data): Return from function immediately if type is unrecognized. * oct-stream.cc (octave_stream::read): Eliminate unnecessary initialization of elts_to_read. * octave-link.cc (F__octave_link_file_dialog__): Eliminate unnecessary initialization of nel. * pr-output.cc (set_real_format): Don't assign to function input variable digits. * str2double.cc (single_num): Initialize return value num at start of function. * ov-complex.cc (octave_complex::double_value, octave_complex::float_value): Eliminate unnecessary initialization of retval. * ov-flt-complex.cc (octave_float_complex::double_value, octave_float_complex::float_value): Eliminate unnecessary initialization of retval. * CSparse.cc (SparseComplexMatrix::inverse): Remove useless asignment to typ. * CSparse.cc (SparseComplexMatrix::bsolve): Initialize anorm before using in comparison. * MatrixType.cc (matrix_complex_probe): Initialize typ to MatrixType::Unknown. * dSparse.cc (SparseMatrix::inverse): Remove useless assignment to typ. * dSparse.cc (SparseMatrix::bsolve): Initialize anorm before using in comparison. * lo-specfun.cc (gammainc): Remove useless assignment to err. * data-conv.cc (oct_data_conv::string_to_data_type): Remove useless assignment to input_is_output. * str-vec.cc (string_vector::list_in_columns): Remove useless assignment to nc.

syntax: regexp
# The recurrent (^|/) idiom in the regexps below should be understood
# to mean "at any directory" while the ^ idiom means "from the
# project's top-level directory".

# gnulib makes these silly backup files
.~$

# This directory gets created by gnulib during the build. 
# It contains no Octave files.
^libgnu/*

# This directory mostly contains cruft during build time, but it does
# contain some Octave code, so we gotta be a bit more careful about
# what we ignore here
^m4/(?!ax_).+\.m4$

# Emacs tools create these
(^|/)TAGS$
(^|/)semantic.cache$

(/|^)Makefile\.in$
^INSTALL$

^aclocal\.m4$
^build-.*($|/)
^configure$
^autom4te\.cache($|/)
^config\.in\.h$

# e.g. doc/faq/OctaveFAQ.info
#      doc/interpreter/octave.info-4
^doc/.*\.info(-\d)?$

^doc/\w*/stamp-vti$
^doc/\w*/version\.texi$
^doc/interpreter/images\.mk$

# e.g. liboctave/operators/smx-op-inc.mk
^liboctave/operators/\w+-op-\w+\.mk$

^libinterp/dldfcn/module\.mk$