Always create /vendor/etc/{passwd,group}

Previously we only created these if the device set
TARGET_FS_CONFIG_GEN, however there are now other targets that want to
depend on these.  Instead of having those targets conditionally depend
on them, we always create them, defaulting to blank contents (by
reading /dev/null for TARGET_FS_CONFIG_GEN).

Test: builds succeed
Change-Id: Ie95286f5a800d891022eb66cd6fefcc967000c2e
diff --git a/tools/fs_config/Android.mk b/tools/fs_config/Android.mk
index a01e702..8a8eca9 100644
--- a/tools/fs_config/Android.mk
+++ b/tools/fs_config/Android.mk
@@ -63,6 +63,8 @@
 my_fs_config_h := $(LOCAL_PATH)/default/$(ANDROID_FS_CONFIG_H)
 endif
 
+system_android_filesystem_config := system/core/include/private/android_filesystem_config.h
+
 ##################################
 include $(CLEAR_VARS)
 LOCAL_SRC_FILES := fs_config_generate.c
@@ -72,8 +74,6 @@
 LOCAL_CFLAGS := -Werror -Wno-error=\#warnings
 
 ifneq ($(TARGET_FS_CONFIG_GEN),)
-system_android_filesystem_config := system/core/include/private/android_filesystem_config.h
-
 # Generate the "generated_oem_aid.h" file
 oem := $(local-generated-sources-dir)/generated_oem_aid.h
 $(oem): PRIVATE_LOCAL_PATH := $(LOCAL_PATH)
@@ -239,19 +239,17 @@
 
 endif
 
-# The newer passwd/group targets are only generated if you
-# use the new TARGET_FS_CONFIG_GEN method.
-ifneq ($(TARGET_FS_CONFIG_GEN),)
-
 ##################################
 # Build the oemaid header library when fs config files are present.
 # Intentionally break build if you require generated AIDs
 # header file, but are not using any fs config files.
+ifneq ($(TARGET_FS_CONFIG_GEN),)
 include $(CLEAR_VARS)
 LOCAL_MODULE := oemaids_headers
 LOCAL_EXPORT_C_INCLUDE_DIRS := $(dir $(my_gen_oem_aid))
 LOCAL_EXPORT_C_INCLUDE_DEPS := $(my_gen_oem_aid)
 include $(BUILD_HEADER_LIBRARY)
+endif
 
 ##################################
 # Generate the vendor/etc/passwd text file for the target
@@ -265,8 +263,11 @@
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
-$(LOCAL_BUILT_MODULE): PRIVATE_LOCAL_PATH := $(LOCAL_PATH)
+ifneq ($(TARGET_FS_CONFIG_GEN),)
 $(LOCAL_BUILT_MODULE): PRIVATE_TARGET_FS_CONFIG_GEN := $(TARGET_FS_CONFIG_GEN)
+else
+$(LOCAL_BUILT_MODULE): PRIVATE_TARGET_FS_CONFIG_GEN := /dev/null
+endif
 $(LOCAL_BUILT_MODULE): PRIVATE_ANDROID_FS_HDR := $(system_android_filesystem_config)
 $(LOCAL_BUILT_MODULE): $(LOCAL_PATH)/fs_config_generator.py $(TARGET_FS_CONFIG_GEN) $(system_android_filesystem_config)
 	@mkdir -p $(dir $@)
@@ -284,15 +285,17 @@
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
-$(LOCAL_BUILT_MODULE): PRIVATE_LOCAL_PATH := $(LOCAL_PATH)
+ifneq ($(TARGET_FS_CONFIG_GEN),)
 $(LOCAL_BUILT_MODULE): PRIVATE_TARGET_FS_CONFIG_GEN := $(TARGET_FS_CONFIG_GEN)
+else
+$(LOCAL_BUILT_MODULE): PRIVATE_TARGET_FS_CONFIG_GEN := /dev/null
+endif
 $(LOCAL_BUILT_MODULE): PRIVATE_ANDROID_FS_HDR := $(system_android_filesystem_config)
 $(LOCAL_BUILT_MODULE): $(LOCAL_PATH)/fs_config_generator.py $(TARGET_FS_CONFIG_GEN) $(system_android_filesystem_config)
 	@mkdir -p $(dir $@)
 	$(hide) $< group --required-prefix=vendor_ --aid-header=$(PRIVATE_ANDROID_FS_HDR) $(PRIVATE_TARGET_FS_CONFIG_GEN) > $@
 
 system_android_filesystem_config :=
-endif
 
 ANDROID_FS_CONFIG_H :=
 my_fs_config_h :=