0. Linker options should be set in the linker tab
1. Same here. We have a separate tab for linker options, because linking is a special, important and very confusing step of the compilation process.
2. We can have "Pass the -O option to the linker" option and be done with it.
3. Can you list them?
4 (p.s.). It was a hack back then... now we'll have to revert it. Are you willing to provide a better patch? One that makes it possible to have a choice control.
5 (p.p.s.). LTO is for advanced users, really! Otherwise it would have been on by default. It is for people who know what is undefined behaviour and how to track and fix any occurrence exposed by LTO. Or are prepared to track compiler bugs.