[Buildroot] [PATCH v4 0/7] Support building a second Barebox config (incl. BBB)

[Pieter Smith]

This patch-set adds support for building barebox with up to 2 configurations.
It can be used to build the barebox x-loader or MLO (also called Secondary
Program Loader) in addition to the standard barebox build (Tertiary Program
Loader). This implements the design proposed in
http://elinux.org/Buildroot#Todo_list, with minor adjustments:
1. Have boot/barebox/barebox.mk contain the common stuff.
2. Add a second package boot/barebox/barebox-2.
3. There is only one version selection, but each package allows to
   define the configuration to be used.
4. Design is a little bit like package/gcc, where we have multiple gcc builds,
   but share a lot of common definitions between the packages.

To demonstrate that it works as advertized, the last patch adds a defconfig for
the beaglebone that makes use of the added functionality.

Revision history:
v4: Introduces barebox-package function to reduce duplication and maintenance
    Simplifies built image selection
    Ease review with smaller patches
    Review re-work: Special thanks to Arnout Vandecappelle and Yegor Yefremov
v3: Updated for master at 544e2c5871f223facd1ab3c2853cd07ad70dd9d1
v2: Dropped x-loader build specialization in favor of 2 generic barebox builds
v1: Initial posting

Pieter Smith (7):
  barebox: support multi-image-build image selection
  barebox: friendly error on missing built image
  barebox: support custom barebox output image name
  barebox: introduce barebox-package function
  barebox: extract package name argument
  barebox: support 2nd config build
  beaglebone: adds barebox bootloader defconfig

 board/beaglebone/barebox.env/boot/sd      |   6 +
 board/beaglebone/barebox.env/config-board |   4 +
 boot/barebox/Config.in                    |  18 +++
 boot/barebox/barebox-2/Config.in          |  79 +++++++++++++
 boot/barebox/barebox-2/barebox-2.hash     |   1 +
 boot/barebox/barebox-2/barebox-2.mk       |   9 ++
 boot/barebox/barebox.mk                   | 178 ++++++++++++++++++------------
 configs/beaglebone_barebox_defconfig      |  41 +++++++
 8 files changed, 266 insertions(+), 70 deletions(-)
 create mode 100644 board/beaglebone/barebox.env/boot/sd
 create mode 100644 board/beaglebone/barebox.env/config-board
 create mode 100644 boot/barebox/barebox-2/Config.in
 create mode 120000 boot/barebox/barebox-2/barebox-2.hash
 create mode 100644 boot/barebox/barebox-2/barebox-2.mk
 create mode 100644 configs/beaglebone_barebox_defconfig

-- 
2.5.0