Deprecate LOCAL_MODULE_TAGS := eng/debug

Uses a new BUILD_BROKEN_ENG_DEBUG_TAGS variable that defaults to true
until we mark all of the broken targets, then we'll switch it to false.

These are fairly trivial to fix, so I don't expect to keep this flag
around for long.

Test: build_test on aosp and internal master; check logs
Change-Id: I6176fec265e78aecff965b7cf1636f831f68a140
diff --git a/core/envsetup.mk b/core/envsetup.mk
index 390a182..f7079fe 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -271,7 +271,8 @@
   BUILD_BROKEN_ANDROIDMK_EXPORTS \
   BUILD_BROKEN_DUP_COPY_HEADERS \
   BUILD_BROKEN_DUP_RULES \
-  BUILD_BROKEN_PHONY_TARGETS
+  BUILD_BROKEN_PHONY_TARGETS \
+  BUILD_BROKEN_ENG_DEBUG_TAGS
 
 $(foreach var,$(vars),$(eval $(var) := $$(strip $$($(var)))))
 
@@ -281,14 +282,10 @@
 
 .KATI_READONLY := $(vars)
 
-CHANGES_URL := https://android.googlesource.com/platform/build/+/master/Changes.md
-
 ifneq ($(BUILD_BROKEN_ANDROIDMK_EXPORTS),true)
 $(KATI_obsolete_export It is a global setting. See $(CHANGES_URL)#export_keyword)
 endif
 
-CHANGES_URL :=
-
 ###########################################
 # Now we can substitute with the real value of TARGET_COPY_OUT_RAMDISK
 ifeq ($(BOARD_BUILD_SYSTEM_ROOT_IMAGE),true)