List of allowed syscalls comes from comments in the form:
#syscalls <list>
for syscalls needed both in passt and pasta mode, and:
#syscalls:pasta <list>
#syscalls:passt <list>
for syscalls specifically needed in pasta or passt mode only.
seccomp.sh builds a list of BPF statements from those comments,
prefixed by a binary search tree to keep lookup fast.
While at it, clean up a bit the Makefile using wildcards.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>