Change amd64 into x86_64 for the arch variable passed to linux since it doesn't play well with the 'amd64' form of writing it. Disable background downloads if tail doesn't support the --pid= argument. Offer to launch a rescue shell if a step fails. Check that all necessary build tools are available before starting to download packages in the background (because wget is included as one of the tools). Build gmp for the toolchain. Fix linux's cfi_ignore fallback for 64-bit (might not be a solution to the actual problem, but it makes it build). Make bash-patches non-critical. Prevent libtool from linking to libraries from the buildhost. Build non-toolchain gnutls without a separate build directory because it otherwise triggers problems on FreeBSD when building an x86_64 AOS (really odd problem). Make copying of sourcefiles to the resulting system non-critical.