Fix build.

Change-Id: I8027e9cb455ac396189b2b8e58588aa1959bb8c0
diff --git a/micro_bench/Android.mk b/micro_bench/Android.mk
index 962b5f0..c5be5f7 100644
--- a/micro_bench/Android.mk
+++ b/micro_bench/Android.mk
@@ -11,12 +11,12 @@
 
 include $(CLEAR_VARS)
 
-LOCAL_SRC_FILES := micro_bench.c
+LOCAL_SRC_FILES := micro_bench.cpp
 
 LOCAL_MODULE_PATH := $(TARGET_OUT_OPTIONAL_EXECUTABLES)
 LOCAL_MODULE_TAGS := debug
 LOCAL_MODULE := micro_bench_static
-LOCAL_STATIC_LIBRARIES = libc
+LOCAL_STATIC_LIBRARIES = libc libm
 LOCAL_FORCE_STATIC_EXECUTABLE := true
 
 include $(BUILD_EXECUTABLE)