to get $"1 right, remove Xqdol() and instead implement it in
terms of Xdol() instruction and use the new Xqw() instruction
to quote the resulting list.
add glob information to the word structure so we wont accidently
deglob quoted strings containing the GLOB. we store Globsize(word)
in in word->glob which avoids recalculating that values and the
check if a word should be globbed quick.
globlist() now substitutes the word inplace avoiding the copying
when all words are literals and avoids recursion.
minor cleanups: use list2str() in execeval(), move octal() to
unix.c, remove the (char*) casts to efree().
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.
