libselinux: LABEL_BACKEND_ANDROID add option to enable

Add option to just enable the android label backend without disabling
anything else eg. using ANDROID_HOST. Enable by default when using ANDROID_HOST.

Signed-off-by: Björn Bidar <bjorn.bidar@jolla.com>

libselinux/Makefile

@@ -4,6 +4,7 @@ PKG_CONFIG ?= pkg-config
 DISABLE_SETRANS ?= n
 DISABLE_RPM ?= n
 ANDROID_HOST ?= n
+LABEL_BACKEND_ANDROID ?= n
 ifeq ($(ANDROID_HOST),y)
 	override DISABLE_SETRANS=y
 	override DISABLE_BOOL=y
@@ -20,7 +21,7 @@ endif
 ifeq ($(DISABLE_X11),y)
 	DISABLE_FLAGS+= -DNO_X_BACKEND
 endif
-export DISABLE_SETRANS DISABLE_RPM DISABLE_FLAGS ANDROID_HOST DISABLE_X11
+export DISABLE_SETRANS DISABLE_RPM DISABLE_FLAGS ANDROID_HOST DISABLE_X11 LABEL_BACKEND_ANDROID
 
 USE_PCRE2 ?= n
 ifeq ($(USE_PCRE2),y)

libselinux/src/Makefile

@@ -122,8 +122,12 @@ SRCS= callbacks.c freecon.c label.c label_file.c \
 	label_backends_android.c regex.c label_support.c \
 	matchpathcon.c setrans_client.c sha1.c booleans.c
 else
-DISABLE_FLAGS+= -DNO_ANDROID_BACKEND
+LABEL_BACKEND_ANDROID=y
+endif
+
+ifneq ($(LABEL_BACKEND_ANDROIDT),y)
 SRCS:= $(filter-out label_backends_android.c, $(SRCS))
+DISABLE_FLAGS+= -DNO_ANDROID_BACKEND
 endif
 
 ifeq ($(DISABLE_X11),y)