Reporters should capture std::clog the same way they do std::cout/cerr

[FabioFracassi]

Description

When code writes output to std::clog (as e.g. boost::log does by default) the output is not handled correctly by reporters that capture output (e.g. JUnit xml).

Steps to reproduce

create a test case that ouputs to std::clog

Extra information

• Catch version: v1.9.5

[horenmar]

The fact that there are two error streams in C++ is one of those things that are obvious in hindsight, but you have to think about them first. I have fixed this locally and it will be in master whenever my internet stops acting up and lets me push.

[philsquared]

so this is now un-clogged?

(sorry, couldn't resist)