http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47836
--- Comment #11 from Ralf Wildenhues <rwild at gcc dot gnu.org> 2011-03-02 05:57:38 UTC --- The automatic enabling of zlib was turned on by revision 152434, a merge of the lto branch. It seems you can use --disable-lto or --with-system-zlib to disable a target zlib from being built. Haven't looked at libiberty yet.
