poky-find-native-sysroot: helper script for locating the native sysroot path

Various poky scripts make use of binaries from the native sysroot.
This helper script can be used to reduce code duplication, and sets
up some environment variables you can use to identify and obtain
the correct filesystem path to the native sysroot.

It works for both in-tree Poky setups as well as toolchain
installations.

Signed-off-by: Scott Garman <scott.a.garman@intel.com>

meta/packages/qemu/qemu-helper-nativesdk_1.0.bb

@@ -10,6 +10,7 @@ SRC_URI = "file://${POKYBASE}/scripts/poky-qemu \
            file://${POKYBASE}/scripts/poky-addptable2image \
            file://${POKYBASE}/scripts/poky-qemu-ifup \
            file://${POKYBASE}/scripts/poky-qemu-ifdown \
+           file://${POKYBASE}/scripts/poky-find-native-sysroot \
            file://tunctl.c \
            file://raw2flash.c \
           "