This implements cross-build for "make release", moving the build into a
container. This way we can support arm, arm64, ppc, and whatnot.
* script/seccomp.sh: separate out of script/release.sh, amend to support
cross-compile and save needed environment variables to a file.
* Dockerfile: add installing libseccomp from source, as this is needed
for release builds.
* script/release.sh: amend to support more architectures in addition to
the native build. Additional arches can be added by specifying
"-a <arch>" argument (can be specified multiple times), or
"make RELEASE_ARGS="-a arm64" release" if called via make.
All supported architectures can be enabled via "make releaseall".
* Makefile: move "release" target to "localrelease", add "release" and
"releaseall" targets to build via the Dockerfile. This is done because
most distros (including Fedora and openSUSE) lack cross-glibc, which is
needed to cross-compile libseccomp.
* Makefile: remove 'cross' and 'localcross' targets, as this is now done
by the release script.
* .github/workflows/validate.yum: amend the release CI job to cross-build
for supported architectures, remove cross job.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Kir Kolyshkin