build: override hardcoded paths to bison and m4 to make the SDK more relocatable

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

Backport of r42300

git-svn-id: svn://svn.openwrt.org/openwrt/branches/barrier_breaker@42301 3c298f89-4303-0410-b956-a3cf2f4a3e73
target/toolchain: strip files, leave out the initial gcc

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

Backport of r42302

git-svn-id: svn://svn.openwrt.org/openwrt/branches/barrier_breaker@42303 3c298f89-4303-0410-b956-a3cf2f4a3e73
kirkwood: add support for legacy devices
generic: backport kernel 3.9 from trunk
kirkwood: add and switch to linux 3.9

Commit "mv643xx_eth: convert to use the Marvell Orion MDIO driver" (c3a07134e6aa5b93a37f72ffa3d11fadf72bf757)
broke DSA switch for all following versions up to now (3.16-rc8).
kirkwood: refresh target and add some features
kirkwood: add support for rd88f6281 as both DT and legacy GatewayNAS profiles
kirkwood: add flash instructions
kirkwood: add wireless to rd88f6281
mac80211: expand mwifiex to support sdio/usb and add missing firmware to mwl8k
kirkwood: add soc audio kmod
kirkwood: improve flash instructions
kirkwood: resuract support for Z0 SOCs
kirkwood: tune kernel config for better energy and speed performance
openssl: allow usage of hardware engines (cryptodev)

Kirkwood manages to gain 300000x more AES performance!
generic: port kernel 3.14 from trunk
mvebu: port platform trunk with kernel 3.14
mac80211: split mwifiex kmods
kirkwood: cosmetic change in flash instructions
kirkwood: add hardware bridging for rd886281 switch