Project: Split CXX compiler id determination to a sharable header.

Configure it separately and include it to process it to determine
the compiler id.
Project: Add another define for determined compiler ids.

This one can be processed by the preprocessor.
Add the WriteCompilerDetectionHeader module.

Provide a function to write a portable header to detect compiler
features.
Merge topic 'WriteCompilerDetectionHeader-module' into next

a36de05b Add the WriteCompilerDetectionHeader module.
bd78a584 Project: Add another define for determined compiler ids.
388bd184 Project: Split CXX compiler id determination to a sharable header.