base/coreos: add ignition as a Flatcar dependency

We add `sys-apps/ignition` as a `coreos-base/coreos` dependency to get
`/usr/libexec/ignition-rmcfg` available on the _real_ root.
Now we want `/usr/bin/ignition` to be in the chroot until it's being copied
to the initramfs but we don't want it on the actual root.

With `PKG_INSTALL_MASK`, we'll prevent `/usr/bin/ignition` to be added
to the image in the `./build_image` - at this time, initramfs is already
created and `sys-apps/ignition` is a binary package.

Signed-off-by: Mathieu Tortuyaux <mtortuyaux@microsoft.com>

sdk_container/src/third_party/coreos-overlay/coreos-base/coreos/coreos-0.0.1.ebuild

@@ -152,6 +152,7 @@ RDEPEND="${RDEPEND}
 	sys-apps/gawk
 	sys-apps/gptfdisk
 	sys-apps/grep
+	sys-apps/ignition
 	sys-apps/iproute2
 	sys-apps/kexec-tools
 	sys-apps/keyutils

sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/make.defaults

@@ -87,6 +87,11 @@ INSTALL_MASK="
   /etc/acpi
 "
 
+# Prevent 'ignition' binary from being installed from sys-apps/ignition binary package.
+PKG_INSTALL_MASK="
+  /usr/bin/ignition
+"
+
 # Keep the default languages small.
 # (not many things respect this though)
 LINGUAS="en"