[git commit] Support configuring Busybox from _defconfig files

[Denys Vlasenko]

commit: http://git.busybox.net/busybox/commit/?id=126f2b2853502a7e74e73c11b86a25510a76b9c0
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master

The existing test .config files are moved to configs/ and renamed
to *_defconfig. 'make xyz_defconfig' will enable the
configuration in that specific file.

Signed-off-by: Daniel Fandrich <dan at coneharvesters.com>
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>

Patch is too large, so refusing to show it