Build block TWRP with RECOVERY_VARIANT

Enable TWRP to reside alongside other recoveries with the naming
convention: bootable/recovery(-flag). If TWRP resides at
bootable/recovery and a device does not specify RECOVERY_VARIANT, then
it will build like normal. If TWRP resides at bootable/recovery-twrp,
then its makefiles will only be parsed if a device specifies
'RECOVERY_VARIANT := twrp'. This prevents TWRP specific makefile
warnings/errors (notably, missing DEVICE_RESOLUTION) when another
recovery is being built.

Change-Id: I8f02fffcd79c309c7123b9428eedc69af02e126e

applypatch/Android.mk

@@ -18,7 +18,10 @@ include $(CLEAR_VARS)
 LOCAL_SRC_FILES := applypatch.c bspatch.c freecache.c imgpatch.c utils.c
 LOCAL_MODULE := libapplypatch
 LOCAL_MODULE_TAGS := eng
-LOCAL_C_INCLUDES += external/bzip2 external/zlib bootable/recovery
+LOCAL_C_INCLUDES += \
+    external/bzip2 \
+    external/zlib \
+    $(commands_recovery_local_path)
 LOCAL_STATIC_LIBRARIES += libmtdutils libmincrypttwrp libbz libz
 
 include $(BUILD_STATIC_LIBRARY)
@@ -27,7 +30,7 @@ include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES := main.c
 LOCAL_MODULE := applypatch
-LOCAL_C_INCLUDES += bootable/recovery
+LOCAL_C_INCLUDES += $(commands_recovery_local_path)
 LOCAL_STATIC_LIBRARIES += libapplypatch libmtdutils libmincrypttwrp libbz libminelf
 LOCAL_SHARED_LIBRARIES += libz libcutils libstdc++ libc
 
@@ -39,7 +42,7 @@ LOCAL_SRC_FILES := main.c
 LOCAL_MODULE := applypatch_static
 LOCAL_FORCE_STATIC_EXECUTABLE := true
 LOCAL_MODULE_TAGS := eng
-LOCAL_C_INCLUDES += bootable/recovery
+LOCAL_C_INCLUDES += $(commands_recovery_local_path)
 LOCAL_STATIC_LIBRARIES += libapplypatch libmtdutils libmincrypttwrp libbz libminelf
 LOCAL_STATIC_LIBRARIES += libz libcutils libstdc++ libc