Botan::secure_scrub_memory -> defined in mem_ops.h
Botan::secure_vector -> defined in secmem.h
The reason only including secmem.h worked in previous (<3.0) versions of
Botan was because secmem.h included mem_ops.h. This is no longer the
case since commit
randombit/botan@49dbbcb2bf (2023-10-11;
"Split out allocator helpers to allocator.h")
Fixes#10038