Port qt5corecompat to auto-generated exports

I don't know why d32f97e59301198b5b909872117ae0b0fbb7ab79 (6.8) didn't
port the module. It's trivial, and helps with adding removed_api.cpp
to this library.

Do it now.

Pick-to: 6.12 6.11 6.8
Change-Id: I4a0e256a24a0a3984c59937ce25f19b1afa85ce7
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>