app-emulation/amazon-ssm-agent: use upstream makefile

By maintaining our own build logic, we missed the fact that the agent
was now split in two parts:
* amazon-ssm-agent in `./core`
* ssm-agent-worker in `./agent`

With the runtimeconfig passed from the `core` to the `agent`.

We were currently shipping `ssm-agent-worker` as the `amazon-ssm-agent`
hence some errors we had.

```
amazon-ssm-agent[8929]: 2023-12-28 15:29:32 WARN [ssm-agent-worker] failed to read runtime config 'identity_config.json': open /var/lib/amazon/ssm/runtimeconfig/identity_config.json: no such file or directory
```

Signed-off-by: Mathieu Tortuyaux <[email protected]>

sdk_container/src/third_party/coreos-overlay/app-emulation/amazon-ssm-agent/amazon-ssm-agent-3.2.985.0-r3.ebuild

@@ -0,0 +1,49 @@
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=7
+
+COREOS_GO_PACKAGE="${GITHUB_URI}"
+COREOS_GO_VERSION="go1.19"
+
+inherit coreos-go-depend golang-vcs-snapshot systemd
+
+EGO_PN="github.com/aws/${PN}"
+DESCRIPTION="AWS Systems Manager Agent"
+HOMEPAGE="https://github.com/aws/amazon-ssm-agent"
+LICENSE="Apache-2.0"
+SRC_URI="https://${EGO_PN}/archive/${PV}.tar.gz -> ${P}.tar.gz ${EGO_VENDOR_URI}"
+SLOT="0"
+KEYWORDS="amd64 arm64"
+
+S="${WORKDIR}/${PN}-${PV}/src/${EGO_PN}"
+
+PATCHES=(
+)
+
+src_prepare() {
+	default
+	ln -s ${PWD}/vendor/src/* ${PWD}/vendor/
+}
+
+src_compile() {
+	go_export
+
+	# set agent release version
+	BRAZIL_PACKAGE_VERSION=${PV} ${EGO} run ./agent/version/versiongenerator/version-gen.go
+	# build all the tools
+	if [[ "${ARCH}" == "arm64" ]]; then
+		emake build-arm64
+	else
+		emake build-linux
+	fi
+}
+
+src_install() {
+	# Folder is like bin/linux_amd64/
+	dobin bin/*/*
+	insinto "/usr/share/amazon/ssm"
+	newins seelog_unix.xml seelog.xml.template
+	doins amazon-ssm-agent.json.template
+
+	systemd_dounit packaging/linux/amazon-ssm-agent.service
+}