Add additional build variable checks to Android.mk files

This was causing the mm command to fail when it was run from
bootable/recovery and no crypto features had been specified in
a device's configuration files

Change-Id: Iddbeea5349bbf75cddb0250cd71821dfe3b7b9d8
diff --git a/crypto/cryptfs/Android.mk b/crypto/cryptfs/Android.mk
index 3267c93..62713fe 100644
--- a/crypto/cryptfs/Android.mk
+++ b/crypto/cryptfs/Android.mk
@@ -1,6 +1,6 @@
 LOCAL_PATH:= $(call my-dir)
 include $(CLEAR_VARS)
-
+ifeq ($(TW_INCLUDE_CRYPTO), true)
 LOCAL_SRC_FILES:= \
 	cryptfs.c
 
@@ -51,3 +51,4 @@
 LOCAL_MODULE_CLASS := UTILITY_EXECUTABLES
 LOCAL_MODULE_PATH := $(PRODUCT_OUT)/utilities
 include $(BUILD_EXECUTABLE)
+endif
\ No newline at end of file