app_process: change app_process a symlink of primary version

Change app_process to be a symlink to the primary version
and have app_process32/app_process64 be the 32-bit/64-bit
versions respectively.

This will make it possible to use the primary zygote for
am/pm commands and other scripts that use app_process and
don't need a specific zygote.

Signed-off-by: Yongqin Liu <yongqin.liu@linaro.org>
Change-Id: Ibef545994eb95ddc82101c95df613ad1d06345e6
diff --git a/cmds/app_process/Android.mk b/cmds/app_process/Android.mk
index 7c25354..74a2f7b 100644
--- a/cmds/app_process/Android.mk
+++ b/cmds/app_process/Android.mk
@@ -1,6 +1,5 @@
 LOCAL_PATH:= $(call my-dir)
 
-# 32-bit app_process
 include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES:= \
@@ -15,10 +14,14 @@
 
 LOCAL_MODULE:= app_process
 LOCAL_MULTILIB := both
-LOCAL_MODULE_STEM_32 := app_process
+LOCAL_MODULE_STEM_32 := app_process32
 LOCAL_MODULE_STEM_64 := app_process64
 include $(BUILD_EXECUTABLE)
 
+# Create a symlink from app_process to app_process32 or 64
+# depending on the target configuration.
+include  $(BUILD_SYSTEM)/executable_prefer_symlink.mk
+
 # Build a variant of app_process binary linked with ASan runtime.
 # ARM-only at the moment.
 ifeq ($(TARGET_ARCH),arm)