l3fwd: some functions are unused in l3fwd-acl

Signed-off-by: Matthew Hall <mhall@mhcomputing.net>
virtio-net.c: incorrect parens around equality check

Signed-off-by: Matthew Hall <mhall@mhcomputing.net>
examples/*: -Wno-switch required for some weird ioctl() ID's

Signed-off-by: Matthew Hall <mhall@mhcomputing.net>
rte.extvars.mk: allow user to override RTE_SDK_BIN

Without this patch it is impossible to compile the examples if you have
compiled the DPDK into the $(RTE_SDK)/build directory, or any other one
besides $(RTE_SDK)/$(RTE_TARGET).

Signed-off-by: Matthew Hall <mhall@mhcomputing.net>