metricsd: build on non-Linux hosts

Bug: 24073089
Change-Id: I94f12f0e30d150348429a959b7bd1c869f766603
diff --git a/metricsd/Android.mk b/metricsd/Android.mk
index 33446e9..03b5739 100644
--- a/metricsd/Android.mk
+++ b/metricsd/Android.mk
@@ -14,8 +14,6 @@
 
 LOCAL_PATH := $(call my-dir)
 
-ifeq ($(HOST_OS),linux)
-
 metrics_cpp_extension := .cc
 libmetrics_sources := \
   c_metrics_library.cc \
@@ -164,5 +162,3 @@
 LOCAL_STATIC_LIBRARIES := libBionicGtestMain libgmock metrics_daemon_protos
 
 include $(BUILD_NATIVE_TEST)
-
-endif # HOST_OS == linux