This documents what I did to change from
  buildroot version 2012.05 to 2014.08

- update README and bin/build-release
  README: change 'br_ver'
  bin/build-release: BR_VER="2012.05"
- update patches to make sure they apply
   ( cd buildroot && QUILT_PATCHES=$PWD/../patches-buildroot quilt push -a )
   remove obsolete patches from series and delete .patch files.
- update default config for all arches
  there has to be a better way to do this, but for now:
   arches=$(for f in conf/buildr*.config; do a=${f##*-}; echo ${a%.*}; done)
   for arch in $arches; do
     make br-config ARCH=$arch
   done
- update path to uclibc config referenced in buildroot-*.conf
   f=".*/uClibc-.*.config"; t="package/uclibc/uClibc-0.9.33.config"
   sed -i -e "s,$f,$t" conf/buildroot-*.config
- update path to busybox config
  Hopefully this was only a one time thing, as i took out the version
  in the path.
  # manually changed to package/busybox/busybox-cirros.config
  vi conf/buildroot-*.config

  Also changed Makefile to address this
- update Makefile for change in location of 'skeleton' in buildroot tree
  Hopefully one time
- update path to device_table.txt
  Hopefully one time.
  f="target/generic/device_table.txt"; t="system/device_table.txt"
  sed -i -e "s,$f,$t,p" conf/buildroot-*.config

- update Makefile for determining busybox version
  Hopefully one time
  now this works: make ARCH=i386 br-busybox-menuconfig

- update busybox config
  make ARCH=i386 br-busybox-menuconfig
  save