Current build system assumes single arch targets to be 32bit and produces 64bit libraries
in an incorrect folder.

The change allows build system to determine proper location of the libraries.

Change-Id: Ic95a36f7108fcae8e6f120f0853ee00e9a8926c1
Reviewed-on: https://swiftshader-review.googlesource.com/17188Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>