Allow building emulator as an sdk-addon

This can be imported into Android Studio more easily, eventually even
as a repository of LineageOS emulator images.

(Build with `m sdk_addon`, it will end up in out/host/linux-x86/sdk_addon)

Change-Id: Ia78524dd729b0f2ccc96f5a6eb2503cdc8b4d253
diff --git a/build/target/product/lineage_generic_target.mk b/build/target/product/lineage_generic_target.mk
index 9dc994e..705f696 100644
--- a/build/target/product/lineage_generic_target.mk
+++ b/build/target/product/lineage_generic_target.mk
@@ -19,3 +19,6 @@
 
 # Allow building otatools
 TARGET_FORCE_OTA_PACKAGE := true
+
+PRODUCT_SDK_ADDON_NAME := lineage
+PRODUCT_SDK_ADDON_SYS_IMG_SOURCE_PROP := $(LOCAL_PATH)/source.properties
diff --git a/build/target/product/source.properties b/build/target/product/source.properties
new file mode 100644
index 0000000..11d524e
--- /dev/null
+++ b/build/target/product/source.properties
@@ -0,0 +1,7 @@
+Pkg.Desc=LineageOS System Image API ${PLATFORM_VERSION} ${TARGET_CPU_ABI}
+Pkg.Revision=1
+AndroidVersion.ApiLevel=${PLATFORM_SDK_VERSION}
+SystemImage.Abi=${TARGET_CPU_ABI}
+SystemImage.TagId=lineage
+SystemImage.TagDisplay=LineageOS
+