[Bug other/61895] libbacktrace crashes with bus error with empty file argv[0]

[vogt at linux dot vnet.ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61895

--- Comment #1 from Dominik Vogt <vogt at linux dot vnet.ibm.com> ---
>   execv(argv[0], &argv[1]);
              ^^^       ^^^
               1         2

Sorry.