Avoid preprocessor include.

Generate header into template instead.
Ensure that the PREFIX is empty when configuring.
Merge topic 'WriteCompilerDetectionHeader-module' into next

dc69e0ac Ensure that the PREFIX is empty when configuring.
3f93d844 Avoid preprocessor include.
Reworked UseSWIG documentation
Merge topic 'UseSWIG-guess_module_name' into next

ec68ce11 Reworked UseSWIG documentation