testing/efibootguard: fix build with gcc 14
Initially tried to upgrade to 0.18, but both 0.18 and 0.17 segfaulted during build. This MR patches the existing version for rebuilding with gcc 14.
Edited by mio
Initially tried to upgrade to 0.18, but both 0.18 and 0.17 segfaulted during build. This MR patches the existing version for rebuilding with gcc 14.