build: Fix build failure on missing oct-parse.h (bug #44391) * libinterp/Makefile.am (GENERATED_MAKE_BUILTINS_INCS): Include parse-tree/oct-parse.h in the list. * libinterp/parse-tree/module.mk (parse-tree/oct-parse.h): Depend on parse-tree/oct-parse.cc.

%!function r = f (x)
%!  if (ischar (x))
%!    r = x;
%!  else
%!    error ("expecting character string");
%!  endif
%!endfunction

%!assert (eval ("f 10;"), "10");