maint: Replace some uses of goto in libinterp. * ls-mat4.cc (read_mat_file_header): Replace "goto data_read_error" with "return -1". * ls-mat4.cc (read_mat_binary_data): Replace "goto data_read_error" with direct call to error. Move variable declarations to point of usage. * ls-mat5.cc (read_mat5_tag, write_mat5_tag): Replace "goto data_read_error" with "return 1". * ls-mat5.cc (save_mat5_binary_element): Replace "goto skip_to_next" with "return true". * ls-oct-binary.cc (read_binary_data): Replace "goto data_read_error" with direct call to error. * mex.cc (valid_key): Replace "goto done" with "return retval". * rand.cc (do_rand): Clarify comment. * pt-binop.cc (tree_binary_expression::rvalue1): Replace "goto done" with "return octave_value (xxx)" * pt-binop.cc (tree_boolean_expression::rvalue1): Replace "goto done" with "return octave_value (xxx)"

% this script is intended to be Matlab compatible
% first, run the script
%
%   ./build_bc_overloads_tests.sh overloads_only
%
% to generate the overloaded functions.
%
ex.double = 1;
ex.single = single (1);
ex.logical = true;
ex.char = 'char';
ex.int8  = int8 (1);
ex.int16 = int16 (1);
ex.int32 = int32 (1);
ex.int64 = int64 (1);
ex.uint8  = uint8 (1);
ex.uint16 = uint16 (1);
ex.uint32 = uint32 (1);
ex.uint64 = uint64 (1);
ex.cell = {};
ex.struct = struct ();
ex.function_handle = @numel;

f = fieldnames (ex);
n = numel (f);

fid = fopen ('bc_overloads_expected','w');
fid
for i = 1:n
  for j = 1:n
    s = tbcover (ex.(f{i}), ex.(f{j}));
    fprintf (fid, '%s %s %s\n', f{i}, f{j}, s);
  end
end
fclose (fid)