Add CONFIG_ROAMING option (off by default)

Change-Id: I846edd8a48e6c5e948732f28caf821055490d320
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
diff --git a/wpa_supplicant/Android.mk b/wpa_supplicant/Android.mk
index 8ad3a28..9d4b997 100644
--- a/wpa_supplicant/Android.mk
+++ b/wpa_supplicant/Android.mk
@@ -35,6 +35,10 @@
 L_CFLAGS += -DANDROID_BRCM_P2P_PATCH
 endif
 
+ifdef CONFIG_ROAMING
+L_CFLAGS += -DCONFIG_ROAMING
+endif
+
 # Use Android specific directory for control interface sockets
 L_CFLAGS += -DCONFIG_CTRL_IFACE_CLIENT_DIR=\"/data/misc/wifi/sockets\"
 L_CFLAGS += -DCONFIG_CTRL_IFACE_DIR=\"/data/system/wpa_supplicant\"