Opatch apply gives warning as following.
OPatch found the word "warning" in the stderr of the make command.
Please look at this stderr. You can re-run this make command.
/usr/bin/ld: warning: libstdc++.so.5, needed by /u01/app/oracle/product/12.1.0/db_1/ctx/lib//libsc_ca.so, not found (try using -rpath or -rpath-link)
Apply the compat-libstdc++-33 rpm as root and try to install the opatch.
yum install compat-libstdc++-33
Issue will be solved.