Remove hacks for old kernels for architectures which require new kernels

* defs.h: Do not define TCB_WAITEXECVE for AARCH64.
* util.c (change_syscall): For AARCH64 and X32, replace code
with dummy "return 0" and a comment explaining why that is ok
for these architectures.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2 files changed