Add build.prop to root ramdisk

will be used for verifying installed bootimage

Change-Id: Iaf80823545980fb2e464a558e918715cc1b82e11
diff --git a/core/Makefile b/core/Makefile
index 43be804..0d07423 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -263,6 +263,21 @@
 	$(hide) echo ro.vendor.build.fingerprint="$(BUILD_FINGERPRINT)">>$@
 endif
 
+# ----------------------------------------------------------------
+# boot.img build.prop
+# as with vendor build.prop above, for verifying that the bootimage
+# build is what we think it is
+
+INSTALLED_BOOTIMAGE_BUILD_PROP_TARGET := $(TARGET_ROOT_OUT)/build.prop
+ALL_DEFAULT_INSTALLED_MODULES += $(INSTALLED_BOOTIMAGE_BUILD_PROP_TARGET)
+$(INSTALLED_BOOTIMAGE_BUILD_PROP_TARGET):
+	@echo Target bootimage buildinfo: $@
+	@mkdir -p $(dir $@)
+	$(hide) echo > $@
+	$(hide) echo ro.bootimage.build.date=`date`>>$@
+	$(hide) echo ro.bootimage.build.date.utc=`date +%s`>>$@
+	$(hide) echo ro.bootimage.build.fingerprint="$(BUILD_FINGERPRINT)">>$@
+
 # -----------------------------------------------------------------
 # sdk-build.prop
 #