centos-7: Ensure libraries in /usr/local/lib{,64} can be found by ldconfig

centos-7/Dockerfile

@@ -341,3 +341,5 @@ RUN yum install -y \
         && \
     yum clean all
 
+ADD ldconfig/local.conf /etc/ld.so.conf.d/local.conf
+RUN ldconfig

centos-7/ldconfig/local.conf

+/usr/local/lib
+/usr/local/lib64