These are added implicitly when you add a library to files_libs

Fixes spurious warnings while building the recipes:

WARNING: No import libraries found for '/libgstvalidate-1.0.a'
WARNING: No import libraries found for '/libgstvalidate-1.0.la'
WARNING: No import libraries found for '/libges-1.0.a'
WARNING: No import libraries found for '/libges-1.0.la'