Xqdol() used to take quadratic time because of strcat(),
the code isnt really needed as list2str() aready does the
same thing in linear time without the strcat().
add estrdup() which uses emalloc() so allocation error are
catched.
move strdups() of name from callers into newvar().
avoid recursion of conclist(), and avoid copying of word
strings by providing Newword() function which doesnt copy
the word string.