[Bug lto/48217] lto mishandles quotes in command line defines

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48217

--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-11-02 
15:13:51 UTC ---
collect2 has extract_string () which handles unquoting from
COLLECT_GCC_OPTIONS.