Catch 2.2.3: compilation fails on platforms that don't support std::tmpfile()

[fschuh]

Description

Catch 2.2.3 has added a new CATCH_CONFIG_EXPERIMENTAL_REDIRECT feature which introduces a dependency on std::tmpfile() even if CATCH_CONFIG_EXPERIMENTAL_REDIRECT is not defined.
This causes Catch to fail to compile on platforms where std::tmpfile() is not available.

It would be best to remove all references to std::tmpfile() except if CATCH_CONFIG_EXPERIMENTAL_REDIRECT is defined.

Steps to reproduce

Try to compile under any platform where std::tmpfile() is not available (several game consoles and embedded systems).

Extra information

• Catch version: v2.2.3
• Operating System: Linux
• Compiler+version: Clang

[horenmar]

This should be now implemented.