DHCPDC: Actually we do have a monotonic clock...

Fix bug http://b/issue?id=6272879

DHCPCD thought that our kernel did not support the posix clock_gettime
and CLOCK_MONOTONIC which could cause an interface flap under just the
right circumstances.  See the writeup in the bug for details.

Change-Id: I3a5325625499d4c3640ce498fc100ab2891d0a9c
diff --git a/Android.mk b/Android.mk
index 68e2166..ffc5866 100644
--- a/Android.mk
+++ b/Android.mk
@@ -15,6 +15,7 @@
 LOCAL_SHARED_LIBRARIES := libc libcutils libnetutils
 LOCAL_MODULE = dhcpcd
 LOCAL_MODULE_TAGS := user
+LOCAL_CFLAGS := -D_POSIX_MONOTONIC_CLOCK -DCLOCK_MONOTONIC
 include $(BUILD_EXECUTABLE)
 
 include $(CLEAR_VARS)