The signal() function of this port may cause handlers to segfault.
In this case, you can either
- uncomment the alternative signal() function in
  src/targets/linux-x86-64/crt0-linux-x86-64.s
  and set SYSLIBC to "/usr/lib/libc.a" in
  src/targets/linux-x86-64/sys-linux-x86-64.h
  (resulting in massively bloated executables)
- or, just not use signal() in your code, if that's an option.
