Convert gsi_skip_mount.cfg to soong

The LOCAL_POST_INSTALL_CMD is problematic for m installclean-less
builds.

Bug: 205632228
Test: presubmits
Change-Id: Id4eb2fd5fbd4f080aec89fa90583ac2ec97c5e1c

target/product/gsi/Android.bp

@@ -23,3 +23,26 @@ filegroup {
         "*.txt",
     ],
 }
+
+prebuilt_etc {
+    name: "gsi_skip_mount.cfg",
+    filename: "skip_mount.cfg",
+    src: "gsi_skip_mount.cfg",
+
+    system_ext_specific: true,
+    relative_install_path: "init/config",
+
+    required: ["gsi_skip_mount_compat_symlink"],
+}
+
+// Adds a symlink under /system/etc/init/config pointing to /system/system_ext/etc/init/config
+// because first-stage init in Android 10.0 will read the skip_mount.cfg from /system/etc/* after
+// chroot /system.
+// TODO: remove this symlink when no need to support new GSI on Android 10.
+// The actual file needs to be under /system/system_ext because it's GSI-specific and does not
+// belong to core CSI.
+install_symlink {
+    name: "gsi_skip_mount_compat_symlink",
+    installed_location: "etc/init/config",
+    symlink_target: "/system/system_ext/etc/init/config",
+}

target/product/gsi/Android.mk

@@ -239,32 +239,6 @@ LOCAL_REQUIRED_MODULES := \
 
 include $(BUILD_PHONY_PACKAGE)
 
-#####################################################################
-# skip_mount.cfg, read by init to skip mounting some partitions when GSI is used.
-
-include $(CLEAR_VARS)
-LOCAL_MODULE := gsi_skip_mount.cfg
-LOCAL_LICENSE_KINDS := SPDX-license-identifier-Apache-2.0
-LOCAL_LICENSE_CONDITIONS := notice
-LOCAL_NOTICE_FILE := build/soong/licenses/LICENSE
-LOCAL_MODULE_STEM := skip_mount.cfg
-LOCAL_SRC_FILES := $(LOCAL_MODULE)
-LOCAL_MODULE_CLASS := ETC
-LOCAL_SYSTEM_EXT_MODULE := true
-LOCAL_MODULE_RELATIVE_PATH := init/config
-
-# Adds a symlink under /system/etc/init/config pointing to /system/system_ext/etc/init/config
-# because first-stage init in Android 10.0 will read the skip_mount.cfg from /system/etc/* after
-# chroot /system.
-# TODO: remove this symlink when no need to support new GSI on Android 10.
-# The actual file needs to be under /system/system_ext because it's GSI-specific and does not
-# belong to core CSI.
-LOCAL_POST_INSTALL_CMD := \
-    mkdir -p $(TARGET_OUT)/etc/init; \
-    ln -sf /system/system_ext/etc/init/config $(TARGET_OUT)/etc/init/config
-
-include $(BUILD_PREBUILT)
-
 #####################################################################
 # init.gsi.rc, GSI-specific init script.
 

target/product/gsi_release.mk

@@ -28,9 +28,8 @@
 
 BUILDING_GSI := true
 
-# Exclude all files under system/product and system/system_ext,
-# and the vndk apex's compat symlinks
 PRODUCT_ARTIFACT_PATH_REQUIREMENT_ALLOWED_LIST += \
+    system/etc/init/config \
     system/product/% \
     system/system_ext/% \
     system/lib/vndk-29 \