pango_1.40.1.bb: Fix compilation error

pango_1.40.1.bb: Fix compilation error

On a build host not having libglib-2.0 installed compiling pango
fails with the error message

./gen-all-unicode: error while loading shared libraries: libglib-2.0.so.0: cannot open shared object file: No such file or directory

The executable doesn't have RPATH set to the library installed in
the native sysroot.

The fix sets RPATH.

Signed-off-by: Dmitry Rozhkov <dmitry.rozhkov@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>