add cpuset support

This moves ActivityManager from using fg/bg cgroups to fg/bg cpusets,
which improves load balancing on appropriate devices.

bug 21782794

Change-Id: Ife149ea551b8b3611a826566b8c8fc8573fdf654
diff --git a/core/jni/Android.mk b/core/jni/Android.mk
index faf926c..5e5450e 100644
--- a/core/jni/Android.mk
+++ b/core/jni/Android.mk
@@ -16,6 +16,10 @@
     LOCAL_CFLAGS += -DPACKED=""
 endif
 
+ifneq ($(ENABLE_CPUSETS),)
+    LOCAL_CFLAGS += -DENABLE_CPUSETS
+endif
+
 LOCAL_CFLAGS += -DGL_GLEXT_PROTOTYPES -DEGL_EGLEXT_PROTOTYPES
 
 LOCAL_CFLAGS += -DU_USING_ICU_NAMESPACE=0