Build build_image and build_super_image as modules.

Bug: 63866463
Test: TreeHugger
Test: `atest releasetools_test`
Test: `atest releasetools_py3_test`
Change-Id: I2059a4ced709d1b2ee331a9aaaa5ca30db4ebf6b
diff --git a/core/tasks/oem_image.mk b/core/tasks/oem_image.mk
index 489feeb..a847b9d 100644
--- a/core/tasks/oem_image.mk
+++ b/core/tasks/oem_image.mk
@@ -34,10 +34,10 @@
 	@mkdir -p $(TARGET_OUT_OEM)
 	@mkdir -p $(oemimage_intermediates) && rm -rf $(oemimage_intermediates)/oem_image_info.txt
 	$(call generate-image-prop-dictionary, $(oemimage_intermediates)/oem_image_info.txt,oem,skip_fsck=true)
-	$(hide) PATH=$(INTERNAL_USERIMAGES_BINARY_PATHS):$$PATH \
-	  build/make/tools/releasetools/build_image.py \
-	  $(TARGET_OUT_OEM) $(oemimage_intermediates)/oem_image_info.txt $@ $(TARGET_OUT)
-	$(hide) $(call assert-max-image-size,$@,$(BOARD_OEMIMAGE_PARTITION_SIZE))
+	PATH=$(INTERNAL_USERIMAGES_BINARY_PATHS):$$PATH \
+	    $(BUILD_IMAGE) \
+	        $(TARGET_OUT_OEM) $(oemimage_intermediates)/oem_image_info.txt $@ $(TARGET_OUT)
+	$(call assert-max-image-size,$@,$(BOARD_OEMIMAGE_PARTITION_SIZE))
 
 .PHONY: oem_image
 oem_image : $(INSTALLED_OEMIMAGE_TARGET)