When I run a any program, compiled against 5.8.0, I get the following:

 $ qtcreator 
qtcreator: relocation error: /usr/lib64/qtcreator/plugins/libHelp.so: symbol _Znwm, version Qt_5 not defined in file libQt5WebEngineCore.so.5 with link time reference

Edited:

Extra symbols are exported by shim allocator which was fixed in QTBUG-57778, unfortunately is was done after 5.8.0 release. This includes operators for new,new[],delete delete[]