Support podman as a drop in replacement for infra/helper.py

[oliverchang]

We could control this via an env var, e.g. OSS_FUZZ_CONTAINER_TOOL=podman

[evverx]

It would be really great if podman was supported. Currently to build projects like systemd and zlib for example it's necessary to point infra/helper.py to a script named docker doing things like

#!/usr/bin/bash

args=()
is_build=false
for a in "$@"; do
  if [[ "$a" == "build" ]]; then
    is_build=true
  elif [[ "$a" =~ ^gcr\.io/oss-fuzz/ && "$is_build" != "true" ]]; then
    args+=("--pull=never")
  fi
  args+=("$a")
done

[ -e /etc/containers/nodocker ] || \
echo "Emulate Docker CLI using podman. Create /etc/containers/nodocker to quiet msg." >&2
exec /usr/bin/podman "${args[@]}"

There are other patches I carry depending on the project but the previous patch is the most important I think. Some things (including that patch) were discussed in #4774.

[oliverchang]

@evverx we have #13973 up. Are you able to help us test this?