node-rdkafka compile in centos 7 failed for not supporting c++14

The `-std=c++14` flag is not supported on GCC 4.8, which is the version used by centos 7. In other words, the compile will be failed in centos 7.
See more on this link https://stackoverflow.com/questions/31965413/compile-c14-code-with-g .

_Originally posted by @yunnysunny in https://github.com/Blizzard/node-rdkafka/issues/892#issuecomment-942918410_

The issue identifies the `-std=c++14` flag and CentOS 7's GCC 4.8 as the failing build context, but names no files or tests. Start by locating where node-rdkafka sets that compiler flag and reproduce the CentOS 7 build; done means the package compiles successfully with the stated toolchain.

Written by the indexing model from the issue text.