logcat: -f run in background

- if saving to file, set SP_BACKGROUND policy
- if saving to file, set BATCH priority
- sort include files

Bug: 19608716
Change-Id: I00acb8b8db0d2ff9ff36c97f9e74604d31938376
diff --git a/logcat/Android.mk b/logcat/Android.mk
index fd54915..7115f9b 100644
--- a/logcat/Android.mk
+++ b/logcat/Android.mk
@@ -5,7 +5,7 @@
 
 LOCAL_SRC_FILES:= logcat.cpp event.logtags
 
-LOCAL_SHARED_LIBRARIES := liblog libbase
+LOCAL_SHARED_LIBRARIES := liblog libbase libcutils
 
 LOCAL_MODULE := logcat