firmware-utils: allow passing a specific MBR signature to ptgen

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@42934 3c298f89-4303-0410-b956-a3cf2f4a3e73
sdk: improve feed setup

 - Add current buildroot scm url as base feed to feeds.conf
 - Prefer feeds.conf over feeds.conf.default when generating the SDK feeds.conf.default

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@42935 3c298f89-4303-0410-b956-a3cf2f4a3e73
x86_64: initial support for PARTUUID

This change configures grub to mount the rootfs by PARTUUID instead of the
device path if CONFIG_TARGET_ROOTFS_PARTNAME is unset.

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@42936 3c298f89-4303-0410-b956-a3cf2f4a3e73