@@ -430,3 +430,5 @@ source "fs/Config.in"
source "boot/Config.in"
source "linux/Config.in"
+
+source "Config.in.legacy"
new file mode 100644
@@ -0,0 +1,51 @@
+#
+# Config.in.legacy - support for backward compatibility
+#
+# When an existing Config.in symbol is removed, it should be added again in this
+# file, and take appropriate action to approximate backward compatibility. If
+# there is an equivalent (set of) new symbols, these can just be select'ed by
+# the old symbol. This makes sure that running 'make oldconfig' will make things
+# "just work" when upgrading to a new buildroot version. If the change is too
+# fundamental and cannot be fixed by a simple select, then the old symbol should
+# select BR2_LEGACY. If that symbol is set, the build will issue an error.
+#
+# When adding legacy symbols to this file, add them to the front. The oldest
+# symbols will be removed again after about two years.
+#
+# The symbol should be copied as-is from the place where it was previously
+# defined, but the help text should be removed or replaced with something that
+# explains how to fix it.
+
+config BR2_LEGACY
+ bool
+ help
+ This option is selected automatically when your old .config uses an
+ option that no longer exists in current buildroot. In that case, the
+ build will fail. Look for config options which are selected in the
+ menu below: they no longer exist and should be replaced by something
+ else.
+
+# This comment fits exactly in a 80-column display
+comment "Legacy detected: check the content of the menu below"
+ depends on BR2_LEGACY
+
+# This option should get a new name with every buildroot release, so it defaults
+# to y again for people who upgrade.
+menuconfig BR2_LEGACY_CHECK_2012_11
+ bool "Check for legacy config options"
+ default y
+ help
+ Select this option to see the config options that are present in your
+ current .config but are no longer supported by buildroot. If any of
+ the options in this menu is selected, they should be replaced with
+ something else. As long as they stay selected, the build will fail.
+ Just de-select this option to automatically remove all the legacy
+ configuration.
+
+if BR2_LEGACY_CHECK_2012_11
+
+#
+# Legacy options from 2012.08
+#
+
+endif
@@ -286,6 +286,12 @@ endif
all: world
+# Include legacy before the other things, because package .mk files
+# may rely on it.
+ifneq ($(BR2_DEPRECATED),y)
+include Makefile.legacy
+endif
+
include package/Makefile.in
include support/dependencies/dependencies.mk
@@ -756,4 +762,3 @@ print-version:
include docs/manual/manual.mk
.PHONY: $(noconfig_targets)
-
new file mode 100644
@@ -0,0 +1,13 @@
+#
+# Makefile.legacy - support for backward compatibility
+#
+# This file contains placeholders to detect backward-compatibility problems.
+# When a buildroot "API" feature is being deprecated, a rule should be added
+# here that issues an error when the old feature is used.
+#
+# This file is not included if BR2_DEPRECATED is selected, so it is possible
+# to bypass the errors (although that's usually a bad idea).
+
+ifeq ($(BR2_LEGACY),y)
+$(error "You have legacy configuration in your .config! Please check your configuration.")
+endif