ld: -rpath must search under sysroot

ld: -rpath must search under sysroot

The -rpath argument would search the host filesystem for libraries,
even when a sysroot was defined.  For cross toolchains with targets
compatible with the host architecture this can find incorrect
libraries.  Leave -rpath-link unmodified, as build systems in the wild
are already using this to point to host directories.

[YOCTO #2965]

(From OE-Core rev: bccea580f1abb762d231f785a4e60c9cd368dcdf)

Signed-off-by: Andy Ross <andy.ross@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>