common/container: move masterdir image building to void-packages

see void-linux/void-docker#11

common/container/docker-bake.hcl

@@ -0,0 +1,29 @@
+variable "MIRROR" {
+  default = "https://repo-ci.voidlinux.org/"
+}
+
+target "docker-metadata-action" {}
+
+target "_common" {
+  inherits = ["docker-metadata-action"]
+  dockerfile = "common/container/Containerfile"
+  no-cache-filter = ["bootstrap"]
+  cache-to = ["type=local,dest=/tmp/buildx-cache"]
+  cache-from = ["type=local,src=/tmp/buildx-cache"]
+  target = "image"
+  args = {
+    "MIRROR" = "${MIRROR}"
+  }
+}
+
+target "void-buildroot-glibc" {
+  inherits = ["_common"]
+  platforms = ["linux/amd64", "linux/386", "linux/arm64", "linux/arm/v7", "linux/arm/v6"]
+  args = { "LIBC" = "glibc" }
+}
+
+target "void-buildroot-musl" {
+  inherits = ["_common"]
+  platforms = ["linux/amd64", "linux/arm64", "linux/arm/v7", "linux/arm/v6"]
+  args = { "LIBC" = "musl" }
+}