@gugurumbe @civodul I guess in this scenario you have a GCC 5.x release archive uncompressed and you're just trying to build it with new GCC, the release archive is already bootstrapped with autoconf so you're not regenerating the build infra needing libtool to be re-run?
@sevan I don’t know if GCC 5.x uses libtool, but if it does, then it’s a compile-time, not bootstrap, thing.