rr - record and replay debugger

Hi!

I found out about rr today.

https://rr-project.org/

It's kind-of an gdb improvement. You run your program as usual, traces
are recorded, then the program run can be analyzed in gdb like usual.

Sadly, it only supports Linux. I tried compiling it and CMake fails with

CMake Error at CMakeLists.txt:338 (message):
  Couldn't find linux/seccomp.h.  You may need to upgrade your kernel.

Quite a number of *seccomp* calls are used in the source code.

I fear it also might need to know about each system call.

Anyway, if someone is looking for a project, this looks quite
interesting.
 Thomas