kernel.bbclass: build host programs with native sysroots
Allow to search header files and libs from native sysroots.
For example, an expanded BUILD_CFLAGS includes:
'-isystem/builddir/to/linux-yocto/recipe-sysroot-native/usr/include'
And an expanded BUILD_LDFLAGS includes:
'-L/builddir/to/linux-yocto/recipe-sysroot-native/usr/lib
-Wl,-rpath-link,/builddir/to/linux-yocto/recipe-sysroot-native/usr/lib
-Wl,-rpath,/builddir/to/linux-yocto/recipe-sysroot-native/usr/lib'
Signed-off-by: Wenzong Fan <wenzong.fan@windriver.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
