* make "IPv6 support" selectable in FREETZ_DL_TOOLCHAIN_OVERRIDE mode (aka self-built toolchain as download-toolchain). The (expert) user is solely responsible for its proper configuration according to the setting used while building the download-toolchain used.
 * refs r9983, refs #1939, refs #1999


git-svn-id: file:///var/svn/freetz/trunk@9989 149334a1-2f27-0410-a3b9-fc62619ac1e6