Enable sync-mac flag for networkd

- This commit enables the sync-mac flag support for
  networkd.

Signed-off-by: Manojkiran Eda <manojkiran.eda@gmail.com>
Change-Id: I4ff7554bd5b60e6cb9f16866aae72b810ea05056
diff --git a/Makefile.am b/Makefile.am
index 3649ca8..d27b304 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -105,6 +105,10 @@
 phosphor_network_manager_CXXFLAGS += -DNIC_SUPPORTS_ETHTOOL
 endif
 
+if FEATURE_SYNC_MAC_FROM_INVENTORY
+phosphor_network_manager_CXXFLAGS += -DSYNC_MAC_FROM_INVENTORY
+endif
+
 xyz/openbmc_project/Network/VLAN/Create/server.cpp: xyz/openbmc_project/Network/VLAN/Create.interface.yaml xyz/openbmc_project/Network/VLAN/Create/server.hpp
 	@mkdir -p `dirname $@`
 	$(SDBUSPLUSPLUS) -r $(srcdir) interface server-cpp xyz.openbmc_project.Network.VLAN.Create > $@