Add options for;

- disk to be created (blank disk given to live-bootstrap) (default)
- disk to already exist but sources downloaded within live-bootstrap
- sources to be downloaded outside live-bootstrap (non-blank disk given
  to live-bootstrap)

Also migrate sysb to use sys_transfer in QEMU mode also.

Note that this means copy_sysc is now irrelevant. sysc is *always*
sourced from sysa.

sysc/init

@@ -7,7 +7,7 @@
 set -e
 
 # shellcheck source=sysa/helpers.sh
-. helpers.sh
+. /usr/src/helpers.sh
 
 export PATH=/usr/bin:/usr/sbin
 export PREFIX=/usr
@@ -54,12 +54,6 @@ install_tar util-linux-2.19.1 0
 # Fix invocation of bash from perl
 ln -s /usr/bin/bash /usr/bin/sh
 
-# Prepare sysc directory structure
-mkdir -p /usr/src
-mv run*.sh /usr/src
-mv helpers.sh SHA256SUMS.pkgs bootstrap.cfg /usr/src
-mv /*-* /usr/src # build scripts
-
 # Check tarballs
 cd "${DISTFILES}"
 sha256sum -c /SHA256SUMS.sources