Instant replay: Debugging C and C++ programs with rr (Red Hat Developer)

Ok. Probably a bit unmanageable for me then data amount wise (GDB already slows things down; I guess rr might not be that much worse?); I tend to work with KiCad for hours.

I tried running KiCad under it. It at least started fast, but died almost immediately, apparently because it uses shared memory, which is IIUC fundamentally incompatible with rr:

```
$ rr record kicad spkr_interface.kicad_pro
rr: Saving execution to trace directory `/home/sliedes/.local/share/rr/kicad-0'.
shared memfd open() failed: Function not implemented
[... some kicad messages]
Trace/breakpoint trap
```