gcc-runtime: Add linux-gnuspe symlink to fix c++ headers

gcc-runtime: Add linux-gnuspe symlink to fix c++ headers

Some architectures can mix different TARGET_OS values, in most cases
we just use one but in the ppc case, can use two different values. In this
case, to use one toolchain with both, we need to ensure the symlinks exist.

This isn't ideal but does fix the ppc toolchains for the release, after
which better ways of handling this can be investiaged. Without this, failures
in the C++ toolchain are seen.

(From OE-Core rev: 112641117f1152bad8a806f1aa872a67575d5316)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>