On Linux both version of the INTERCEPT_FUNCTION macro now return true
when interception was successful. Adapt and cleanup some usages.
Also note that &(func) == &WRAP(func) is a link-time property, but we
do a runtime check.
Tested on Linux and macOS.
Previous attempt reverted by: 5642c3feb03d020dc06a62e3dc54f3206a97a391
This attempt to bring order to the interceptor macro goes the other
direction and aligns the Linux implementation with the way things are
done on Windows.