Just thought I would pass along some knowledge I came into today while installing Oracle 126.96.36.199 on CentOS 6. Oracle has an RPM that will install all the required packages if you are using Oracle Enterprise Linux, but for those of us using RHEL or some other derivative, here are the packages:
yum install compat-libcap1 compat-libstdc++-33 gcc gcc-c++ glibc glibc-devel libgcc libstdc++ libstdc++-devel libaio libaio-devel libXext libXtst libX11 libXau libxcb libXi make sysstat compat-libstdc++-33.i686 glibc.i686 glibc-devel.i686 libgcc.i686 libstdc++.i686 libstdc++-devel.i686 libaio.i686 libaio-devel.i686 libXext.i686 libXtst.i686 libX11.i686 libXau.i686 libxcb.i686 libXi.i686
The info above was pulled from this document and formatted for the command line:
Hopefully this will help someone and save them from having to run the information down, then pull it, format it, etc. Unlike the 11g installer, the 12c installer does not tell you what packages you are missing.