Update apidiff.mk to use the sdk-name macro.

This internal change complements aosp/661901, which introduced the sdk
module name macro. apidiff.mk doesn't exist in aosp.

Bug: 77525052
Test: make droid
Change-Id: Ia347d8ffef1a7d28508256b4a5c984b3e07ed998
(cherry picked from commit d4e657a2277c3c8491be145a87f69c7572e181b6)
diff --git a/core/apidiff.mk b/core/apidiff.mk
index 36d75fe..180aabd 100644
--- a/core/apidiff.mk
+++ b/core/apidiff.mk
@@ -57,12 +57,11 @@
     LOCAL_JAVA_LIBRARIES := android_test_stubs_current $(LOCAL_JAVA_LIBRARIES)
     $(full_target): PRIVATE_BOOTCLASSPATH := $(call java-lib-files, android_test_stubs_current)
   else
-    # core_<ver> is subset of <ver>. Instead of defining a prebuilt lib for core_<ver>,
-    # use the stub for <ver> when building for apps.
-    _version := $(patsubst core_%,%,$(LOCAL_SDK_VERSION))
-    LOCAL_JAVA_LIBRARIES := sdk_v$(_version) $(LOCAL_JAVA_LIBRARIES)
-    $(full_target): PRIVATE_BOOTCLASSPATH := $(call java-lib-files, sdk_v$(_version))
-    _version :=
+    # TARGET_BUILD_APPS is set. Use the modules defined in prebuilts/sdk/Android.mk.
+    _module_name := $(call resolve-prebuilt-sdk-module,$(LOCAL_SDK_VERSION))
+    LOCAL_JAVA_LIBRARIES := $(_module_name) $(LOCAL_JAVA_LIBRARIES)
+    $(full_target): PRIVATE_BOOTCLASSPATH := $(call java-lib-files, $(_module_name))
+    _module_name :=
   endif
 else
   LOCAL_JAVA_LIBRARIES := core-oj core-libart ext framework $(LOCAL_JAVA_LIBRARIES)