rpm macro resolution should take the target architecture into account

[joshiste]

When evaluating the %{_libdir} macro the target architecture must be taken into account.
On a 64bit machine it makes a difference:

$ rpm --eval %{_libdir}
/usr/lib64
$ rpm --target noarch-pc-linux --eval %{_libdir}
/usr/lib

so you may endup that files are copied to a different location then the rpm is looking for when building the spec