Load structures with arbitrary string fieldnames (bug #50831, bug #46645). * ls-oct-text.h, ls-oct-text.cc (read_text_data): Consider additional optional bool argument to skip validation of input name. * ov-struct.cc (octave_struct::load_ascii, octave_scalar_struct::load_ascii): Call read_text_data with additional argument (skip_validation), set to true. * test/bug-50831/bug-50831.tst, test/bug-50831/module.mk: New test files.

%!test
%! filename = "save-text.var";
%! s.("a-b") = "bad fieldname";
%! unwind_protect
%!   save ("-text", filename, "s");
%!   filevar = load (filename);
%!   assert (filevar.s, s);
%! unwind_protect_cleanup
%!   sts = unlink (filename);
%! end_unwind_protect