Use prebuilt m4 instead of system m4

Bug: 117561006
Test: treehugger
Change-Id: Id794aed10fdffef10490561d2cfeb2a92801b331
diff --git a/Android.mk b/Android.mk
index 1779ff2..a58ecbe 100644
--- a/Android.mk
+++ b/Android.mk
@@ -345,6 +345,10 @@
 
 # sepolicy_policy.conf - All of the policy for the device.  This is only used to
 # check neverallow rules.
+policy_files := $(call build_policy, $(sepolicy_build_files), \
+  $(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY) $(PLAT_VENDOR_POLICY) \
+  $(PRODUCT_PUBLIC_POLICY) $(PRODUCT_PRIVATE_POLICY) \
+  $(BOARD_VENDOR_SEPOLICY_DIRS) $(BOARD_ODM_SEPOLICY_DIRS))
 sepolicy_policy.conf := $(intermediates)/policy.conf
 $(sepolicy_policy.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
 $(sepolicy_policy.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
@@ -354,15 +358,17 @@
 $(sepolicy_policy.conf): PRIVATE_TGT_WITH_NATIVE_COVERAGE := $(with_native_coverage)
 $(sepolicy_policy.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
 $(sepolicy_policy.conf): PRIVATE_SEPOLICY_SPLIT := $(PRODUCT_SEPOLICY_SPLIT)
-$(sepolicy_policy.conf): $(call build_policy, $(sepolicy_build_files), \
-$(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY) $(PLAT_VENDOR_POLICY) \
-$(PRODUCT_PUBLIC_POLICY) $(PRODUCT_PRIVATE_POLICY) \
-$(BOARD_VENDOR_SEPOLICY_DIRS) $(BOARD_ODM_SEPOLICY_DIRS))
+$(sepolicy_policy.conf): PRIVATE_POLICY_FILES := $(policy_files)
+$(sepolicy_policy.conf): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 	$(hide) sed '/^\s*dontaudit.*;/d' $@ | sed '/^\s*dontaudit/,/;/d' > $@.dontaudit
 
 # sepolicy_policy_2.conf - All of the policy for the device.  This is only used to
 # check neverallow rules using sepolicy-analyze, similar to CTS.
+policy_files := $(call build_policy, $(sepolicy_build_files), \
+  $(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY) $(PLAT_VENDOR_POLICY) \
+  $(PRODUCT_PUBLIC_POLICY) $(PRODUCT_PRIVATE_POLICY) \
+  $(BOARD_VENDOR_SEPOLICY_DIRS) $(BOARD_ODM_SEPOLICY_DIRS))
 sepolicy_policy_2.conf := $(intermediates)/policy_2.conf
 $(sepolicy_policy_2.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
 $(sepolicy_policy_2.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
@@ -373,10 +379,8 @@
 $(sepolicy_policy_2.conf): PRIVATE_TGT_WITH_NATIVE_COVERAGE := $(with_native_coverage)
 $(sepolicy_policy_2.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
 $(sepolicy_policy_2.conf): PRIVATE_SEPOLICY_SPLIT := $(PRODUCT_SEPOLICY_SPLIT)
-$(sepolicy_policy_2.conf): $(call build_policy, $(sepolicy_build_files), \
-$(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY) $(PLAT_VENDOR_POLICY) \
-$(PRODUCT_PUBLIC_POLICY) $(PRODUCT_PRIVATE_POLICY) \
-$(BOARD_VENDOR_SEPOLICY_DIRS) $(BOARD_ODM_SEPOLICY_DIRS))
+$(sepolicy_policy_2.conf): PRIVATE_POLICY_FILES := $(policy_files)
+$(sepolicy_policy_2.conf): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 	$(hide) sed '/^\s*dontaudit.*;/d' $@ | sed '/^\s*dontaudit/,/;/d' > $@.dontaudit
 
@@ -409,6 +413,7 @@
 # the compilation of public policy and subsequent removal of CIL policy that
 # should not be exported.
 
+policy_files := $(call build_policy, $(sepolicy_build_files), $(REQD_MASK_POLICY))
 reqd_policy_mask.conf := $(intermediates)/reqd_policy_mask.conf
 $(reqd_policy_mask.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
 $(reqd_policy_mask.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
@@ -419,7 +424,8 @@
 $(reqd_policy_mask.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
 $(reqd_policy_mask.conf): PRIVATE_SEPOLICY_SPLIT := $(PRODUCT_SEPOLICY_SPLIT)
 $(reqd_policy_mask.conf): PRIVATE_COMPATIBLE_PROPERTY := $(PRODUCT_COMPATIBLE_PROPERTY)
-$(reqd_policy_mask.conf): $(call build_policy, $(sepolicy_build_files), $(REQD_MASK_POLICY))
+$(reqd_policy_mask.conf): PRIVATE_POLICY_FILES := $(policy_files)
+$(reqd_policy_mask.conf): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 # b/37755687
 CHECKPOLICY_ASAN_OPTIONS := ASAN_OPTIONS=detect_leaks=0
@@ -438,6 +444,8 @@
 # policy that would not compile in checkpolicy on its own.  To get around this
 # limitation, add only the required files from private policy, which will
 # generate CIL policy that will then be filtered out by the reqd_policy_mask.
+policy_files := $(call build_policy, $(sepolicy_build_files), \
+  $(PLAT_PUBLIC_POLICY) $(PRODUCT_PUBLIC_POLICY) $(REQD_MASK_POLICY))
 pub_policy.conf := $(intermediates)/pub_policy.conf
 $(pub_policy.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
 $(pub_policy.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
@@ -448,8 +456,8 @@
 $(pub_policy.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
 $(pub_policy.conf): PRIVATE_SEPOLICY_SPLIT := $(PRODUCT_SEPOLICY_SPLIT)
 $(pub_policy.conf): PRIVATE_COMPATIBLE_PROPERTY := $(PRODUCT_COMPATIBLE_PROPERTY)
-$(pub_policy.conf): $(call build_policy, $(sepolicy_build_files), \
-$(PLAT_PUBLIC_POLICY) $(PRODUCT_PUBLIC_POLICY) $(REQD_MASK_POLICY))
+$(pub_policy.conf): PRIVATE_POLICY_FILES := $(policy_files)
+$(pub_policy.conf): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 pub_policy.cil := $(intermediates)/pub_policy.cil
 $(pub_policy.cil): PRIVATE_POL_CONF := $(pub_policy.conf)
@@ -464,6 +472,8 @@
 pub_policy.conf :=
 
 ##################################
+policy_files := $(call build_policy, $(sepolicy_build_files), \
+  $(PLAT_PUBLIC_POLICY) $(REQD_MASK_POLICY))
 plat_pub_policy.conf := $(intermediates)/plat_pub_policy.conf
 $(plat_pub_policy.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
 $(plat_pub_policy.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
@@ -474,8 +484,8 @@
 $(plat_pub_policy.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
 $(plat_pub_policy.conf): PRIVATE_SEPOLICY_SPLIT := $(PRODUCT_SEPOLICY_SPLIT)
 $(plat_pub_policy.conf): PRIVATE_COMPATIBLE_PROPERTY := $(PRODUCT_COMPATIBLE_PROPERTY)
-$(plat_pub_policy.conf): $(call build_policy, $(sepolicy_build_files), \
-$(PLAT_PUBLIC_POLICY) $(REQD_MASK_POLICY))
+$(plat_pub_policy.conf): PRIVATE_POLICY_FILES := $(policy_files)
+$(plat_pub_policy.conf): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 
 plat_pub_policy.cil := $(intermediates)/plat_pub_policy.cil
@@ -503,6 +513,8 @@
 # plat_policy.conf - A combination of the private and public platform policy
 # which will ship with the device.  The platform will always reflect the most
 # recent platform version and is not currently being attributized.
+policy_files := $(call build_policy, $(sepolicy_build_files), \
+  $(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY))
 plat_policy.conf := $(intermediates)/plat_policy.conf
 $(plat_policy.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
 $(plat_policy.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
@@ -513,8 +525,8 @@
 $(plat_policy.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
 $(plat_policy.conf): PRIVATE_SEPOLICY_SPLIT := $(PRODUCT_SEPOLICY_SPLIT)
 $(plat_policy.conf): PRIVATE_COMPATIBLE_PROPERTY := $(PRODUCT_COMPATIBLE_PROPERTY)
-$(plat_policy.conf): $(call build_policy, $(sepolicy_build_files), \
-$(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY))
+$(plat_policy.conf): PRIVATE_POLICY_FILES := $(policy_files)
+$(plat_policy.conf): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 	$(hide) sed '/^\s*dontaudit.*;/d' $@ | sed '/^\s*dontaudit/,/;/d' > $@.dontaudit
 
@@ -546,6 +558,8 @@
 include $(BUILD_SYSTEM)/base_rules.mk
 
 # userdebug_plat_policy.conf - the userdebug version plat_sepolicy.cil
+policy_files := $(call build_policy, $(sepolicy_build_files), \
+  $(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY))
 userdebug_plat_policy.conf := $(intermediates)/userdebug_plat_policy.conf
 $(userdebug_plat_policy.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
 $(userdebug_plat_policy.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
@@ -556,8 +570,8 @@
 $(userdebug_plat_policy.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
 $(userdebug_plat_policy.conf): PRIVATE_SEPOLICY_SPLIT := $(PRODUCT_SEPOLICY_SPLIT)
 $(userdebug_plat_policy.conf): PRIVATE_COMPATIBLE_PROPERTY := $(PRODUCT_COMPATIBLE_PROPERTY)
-$(userdebug_plat_policy.conf): $(call build_policy, $(sepolicy_build_files), \
-$(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY))
+$(userdebug_plat_policy.conf): PRIVATE_POLICY_FILES := $(policy_files)
+$(userdebug_plat_policy.conf): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 	$(hide) sed '/^\s*dontaudit.*;/d' $@ | sed '/^\s*dontaudit/,/;/d' > $@.dontaudit
 
@@ -590,6 +604,9 @@
 
 # product_policy.conf - A combination of the private and public product policy
 # which will ship with the device. Product policy is not attributized.
+policy_files := $(call build_policy, $(sepolicy_build_files), \
+  $(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY) \
+  $(PRODUCT_PUBLIC_POLICY) $(PRODUCT_PRIVATE_POLICY))
 product_policy.conf := $(intermediates)/product_policy.conf
 $(product_policy.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
 $(product_policy.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
@@ -600,9 +617,8 @@
 $(product_policy.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
 $(product_policy.conf): PRIVATE_SEPOLICY_SPLIT := $(PRODUCT_SEPOLICY_SPLIT)
 $(product_policy.conf): PRIVATE_COMPATIBLE_PROPERTY := $(PRODUCT_COMPATIBLE_PROPERTY)
-$(product_policy.conf): $(call build_policy, $(sepolicy_build_files), \
-$(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY) \
-$(PRODUCT_PUBLIC_POLICY) $(PRODUCT_PRIVATE_POLICY))
+$(product_policy.conf): PRIVATE_POLICY_FILES := $(policy_files)
+$(product_policy.conf): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 	$(hide) sed '/dontaudit/d' $@ > $@.dontaudit
 
@@ -732,6 +748,9 @@
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
+policy_files := $(call build_policy, $(sepolicy_build_files), \
+  $(PLAT_PUBLIC_POLICY) $(PRODUCT_PUBLIC_POLICY) $(REQD_MASK_POLICY) $(PLAT_VENDOR_POLICY) \
+  $(BOARD_VENDOR_SEPOLICY_DIRS))
 vendor_policy.conf := $(intermediates)/vendor_policy.conf
 $(vendor_policy.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
 $(vendor_policy.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
@@ -742,9 +761,8 @@
 $(vendor_policy.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
 $(vendor_policy.conf): PRIVATE_SEPOLICY_SPLIT := $(PRODUCT_SEPOLICY_SPLIT)
 $(vendor_policy.conf): PRIVATE_COMPATIBLE_PROPERTY := $(PRODUCT_COMPATIBLE_PROPERTY)
-$(vendor_policy.conf): $(call build_policy, $(sepolicy_build_files), \
-$(PLAT_PUBLIC_POLICY) $(PRODUCT_PUBLIC_POLICY) $(REQD_MASK_POLICY) $(PLAT_VENDOR_POLICY) \
-$(BOARD_VENDOR_SEPOLICY_DIRS))
+$(vendor_policy.conf): PRIVATE_POLICY_FILES := $(policy_files)
+$(vendor_policy.conf): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 	$(hide) sed '/^\s*dontaudit.*;/d' $@ | sed '/^\s*dontaudit/,/;/d' > $@.dontaudit
 
@@ -783,6 +801,9 @@
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
+policy_files := $(call build_policy, $(sepolicy_build_files), \
+  $(PLAT_PUBLIC_POLICY) $(PRODUCT_PUBLIC_POLICY) $(REQD_MASK_POLICY) $(PLAT_VENDOR_POLICY) \
+  $(BOARD_VENDOR_SEPOLICY_DIRS) $(BOARD_ODM_SEPOLICY_DIRS))
 odm_policy.conf := $(intermediates)/odm_policy.conf
 $(odm_policy.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
 $(odm_policy.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
@@ -793,9 +814,8 @@
 $(odm_policy.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
 $(odm_policy.conf): PRIVATE_SEPOLICY_SPLIT := $(PRODUCT_SEPOLICY_SPLIT)
 $(odm_policy.conf): PRIVATE_COMPATIBLE_PROPERTY := $(PRODUCT_COMPATIBLE_PROPERTY)
-$(odm_policy.conf): $(call build_policy, $(sepolicy_build_files), \
-  $(PLAT_PUBLIC_POLICY) $(PRODUCT_PUBLIC_POLICY) $(REQD_MASK_POLICY) $(PLAT_VENDOR_POLICY) \
-  $(BOARD_VENDOR_SEPOLICY_DIRS) $(BOARD_ODM_SEPOLICY_DIRS))
+$(odm_policy.conf): PRIVATE_POLICY_FILES := $(policy_files)
+$(odm_policy.conf): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 	$(hide) sed '/^\s*dontaudit.*;/d' $@ | sed '/^\s*dontaudit/,/;/d' > $@.dontaudit
 
@@ -1001,6 +1021,11 @@
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
+policy_files := $(call build_policy, $(sepolicy_build_files), \
+  $(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY) \
+  $(PRODUCT_PUBLIC_POLICY) $(PRODUCT_PRIVATE_POLICY) \
+  $(PLAT_VENDOR_POLICY) $(BOARD_VENDOR_SEPOLICY_DIRS) \
+  $(BOARD_ODM_SEPOLICY_DIRS))
 sepolicy.recovery.conf := $(intermediates)/sepolicy.recovery.conf
 $(sepolicy.recovery.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
 $(sepolicy.recovery.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
@@ -1010,11 +1035,8 @@
 $(sepolicy.recovery.conf): PRIVATE_TGT_WITH_NATIVE_COVERAGE := $(with_native_coverage)
 $(sepolicy.recovery.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
 $(sepolicy.recovery.conf): PRIVATE_TGT_RECOVERY := -D target_recovery=true
-$(sepolicy.recovery.conf): $(call build_policy, $(sepolicy_build_files), \
-                           $(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY) \
-                           $(PRODUCT_PUBLIC_POLICY) $(PRODUCT_PRIVATE_POLICY) \
-                           $(PLAT_VENDOR_POLICY) $(BOARD_VENDOR_SEPOLICY_DIRS) \
-                           $(BOARD_ODM_SEPOLICY_DIRS))
+$(sepolicy.recovery.conf): PRIVATE_POLICY_FILES := $(policy_files)
+$(sepolicy.recovery.conf): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 	$(hide) sed '/^\s*dontaudit.*;/d' $@ | sed '/^\s*dontaudit/,/;/d' > $@.dontaudit
 
@@ -1052,6 +1074,8 @@
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
+policy_files := $(call build_policy, $(sepolicy_build_files), \
+  $(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY))
 $(LOCAL_BUILT_MODULE): PRIVATE_MLS_SENS := $(MLS_SENS)
 $(LOCAL_BUILT_MODULE): PRIVATE_MLS_CATS := $(MLS_CATS)
 $(LOCAL_BUILT_MODULE): PRIVATE_TARGET_BUILD_VARIANT := user
@@ -1060,8 +1084,8 @@
 $(LOCAL_BUILT_MODULE): PRIVATE_SEPOLICY_SPLIT := cts
 $(LOCAL_BUILT_MODULE): PRIVATE_COMPATIBLE_PROPERTY := cts
 $(LOCAL_BUILT_MODULE): PRIVATE_EXCLUDE_BUILD_TEST := true
-$(LOCAL_BUILT_MODULE): $(call build_policy, $(sepolicy_build_files), \
-$(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY))
+$(LOCAL_BUILT_MODULE): PRIVATE_POLICY_FILES := $(policy_files)
+$(LOCAL_BUILT_MODULE): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 	$(hide) sed '/^\s*dontaudit.*;/d' $@ | sed '/^\s*dontaudit/,/;/d' > $@.dontaudit
 
@@ -1114,9 +1138,10 @@
 endif
 
 file_contexts.local.tmp := $(intermediates)/file_contexts.local.tmp
-$(file_contexts.local.tmp): $(local_fc_files)
+$(file_contexts.local.tmp): PRIVATE_FC_FILES := $(local_fc_files)
+$(file_contexts.local.tmp): $(local_fc_files) $(M4)
 	@mkdir -p $(dir $@)
-	$(hide) m4 --fatal-warnings -s $^ > $@
+	$(hide) $(M4) --fatal-warnings -s $(PRIVATE_FC_FILES) > $@
 
 device_fc_files := $(call build_vendor_policy, file_contexts)
 
@@ -1126,9 +1151,10 @@
 
 file_contexts.device.tmp := $(intermediates)/file_contexts.device.tmp
 $(file_contexts.device.tmp): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
-$(file_contexts.device.tmp): $(device_fc_files)
+$(file_contexts.device.tmp): PRIVATE_DEVICE_FC_FILES := $(device_fc_files)
+$(file_contexts.device.tmp): $(device_fc_files) $(M4)
 	@mkdir -p $(dir $@)
-	$(hide) m4 --fatal-warnings -s $(PRIVATE_ADDITIONAL_M4DEFS) $^ > $@
+	$(hide) $(M4) --fatal-warnings -s $(PRIVATE_ADDITIONAL_M4DEFS) $(PRIVATE_DEVICE_FC_FILES) > $@
 
 file_contexts.device.sorted.tmp := $(intermediates)/file_contexts.device.sorted.tmp
 $(file_contexts.device.sorted.tmp): PRIVATE_SEPOLICY := $(built_sepolicy)
@@ -1139,9 +1165,10 @@
 	$(hide) $(HOST_OUT_EXECUTABLES)/fc_sort -i $< -o $@
 
 file_contexts.concat.tmp := $(intermediates)/file_contexts.concat.tmp
-$(file_contexts.concat.tmp): $(file_contexts.local.tmp) $(file_contexts.device.sorted.tmp)
+$(file_contexts.concat.tmp): PRIVATE_CONTEXTS := $(file_contexts.local.tmp) $(file_contexts.device.sorted.tmp)
+$(file_contexts.concat.tmp): $(file_contexts.local.tmp) $(file_contexts.device.sorted.tmp) $(M4)
 	@mkdir -p $(dir $@)
-	$(hide) m4 --fatal-warnings -s $^ > $@
+	$(hide) $(M4) --fatal-warnings -s $(PRIVATE_CONTEXTS) > $@
 
 $(LOCAL_BUILT_MODULE): PRIVATE_SEPOLICY := $(built_sepolicy)
 $(LOCAL_BUILT_MODULE): $(file_contexts.concat.tmp) $(built_sepolicy) $(HOST_OUT_EXECUTABLES)/sefcontext_compile $(HOST_OUT_EXECUTABLES)/checkfc
@@ -1199,9 +1226,9 @@
 vndservice_contexts.tmp := $(intermediates)/vndservice_contexts.tmp
 $(vndservice_contexts.tmp): PRIVATE_SVC_FILES := $(vnd_svcfiles)
 $(vndservice_contexts.tmp): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
-$(vndservice_contexts.tmp): $(vnd_svcfiles)
+$(vndservice_contexts.tmp): $(vnd_svcfiles) $(M4)
 	@mkdir -p $(dir $@)
-	$(hide) m4 --fatal-warnings -s $(PRIVATE_ADDITIONAL_M4DEFS) $(PRIVATE_SVC_FILES) > $@
+	$(hide) $(M4) --fatal-warnings -s $(PRIVATE_ADDITIONAL_M4DEFS) $(PRIVATE_SVC_FILES) > $@
 
 $(LOCAL_BUILT_MODULE): PRIVATE_SEPOLICY := $(built_sepolicy)
 $(LOCAL_BUILT_MODULE): $(vndservice_contexts.tmp) $(built_sepolicy) $(HOST_OUT_EXECUTABLES)/checkfc $(ACP)
@@ -1249,6 +1276,8 @@
 # to enable partners to add their own compatibility mapping
 BASE_PLAT_PUBLIC_POLICY := $(filter-out $(BOARD_PLAT_PUBLIC_SEPOLICY_DIR), $(PLAT_PUBLIC_POLICY))
 BASE_PLAT_PRIVATE_POLICY := $(filter-out $(BOARD_PLAT_PRIVATE_SEPOLICY_DIR), $(PLAT_PRIVATE_POLICY))
+policy_files := $(call build_policy, $(sepolicy_build_files), \
+  $(BASE_PLAT_PUBLIC_POLICY) $(BASE_PLAT_PRIVATE_POLICY))
 base_plat_policy.conf := $(intermediates)/base_plat_policy.conf
 $(base_plat_policy.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
 $(base_plat_policy.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
@@ -1258,8 +1287,8 @@
 $(base_plat_policy.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
 $(base_plat_policy.conf): PRIVATE_SEPOLICY_SPLIT := true
 $(base_plat_policy.conf): PRIVATE_COMPATIBLE_PROPERTY := $(PRODUCT_COMPATIBLE_PROPERTY)
-$(base_plat_policy.conf): $(call build_policy, $(sepolicy_build_files), \
-$(BASE_PLAT_PUBLIC_POLICY) $(BASE_PLAT_PRIVATE_POLICY))
+$(base_plat_policy.conf): PRIVATE_POLICY_FILES := $(policy_files)
+$(base_plat_policy.conf): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 	$(hide) sed '/^\s*dontaudit.*;/d' $@ | sed '/^\s*dontaudit/,/;/d' > $@.dontaudit
 
@@ -1277,6 +1306,8 @@
 	$(hide) cat $(PRIVATE_ADDITIONAL_CIL_FILES) >> $@
 	$(hide) $(HOST_OUT_EXECUTABLES)/secilc -m -M true -G -c $(POLICYVERS) $(PRIVATE_NEVERALLOW_ARG) $@ -o $@ -f /dev/null
 
+policy_files := $(call build_policy, $(sepolicy_build_files), \
+  $(BASE_PLAT_PUBLIC_POLICY) $(REQD_MASK_POLICY))
 base_plat_pub_policy.conf := $(intermediates)/base_plat_pub_policy.conf
 $(base_plat_pub_policy.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
 $(base_plat_pub_policy.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
@@ -1286,8 +1317,8 @@
 $(base_plat_pub_policy.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
 $(base_plat_pub_policy.conf): PRIVATE_SEPOLICY_SPLIT := true
 $(base_plat_pub_policy.conf): PRIVATE_COMPATIBLE_PROPERTY := $(PRODUCT_COMPATIBLE_PROPERTY)
-$(base_plat_pub_policy.conf): $(call build_policy, $(sepolicy_build_files), \
-$(BASE_PLAT_PUBLIC_POLICY) $(REQD_MASK_POLICY))
+$(base_plat_pub_policy.conf): PRIVATE_POLICY_FILES := $(policy_files)
+$(base_plat_pub_policy.conf): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 
 base_plat_pub_policy.cil := $(intermediates)/base_plat_pub_policy.cil
diff --git a/build/soong/selinux_contexts.go b/build/soong/selinux_contexts.go
index 632237c..020357a 100644
--- a/build/soong/selinux_contexts.go
+++ b/build/soong/selinux_contexts.go
@@ -263,7 +263,8 @@
 	rule := android.NewRuleBuilder()
 
 	rule.Command().
-		Text("m4 --fatal-warnings -s").
+		Tool(ctx.Config().PrebuiltBuildTool(ctx, "m4")).
+		Text("--fatal-warnings -s").
 		FlagForEachArg("-D", ctx.DeviceConfig().SepolicyM4Defs()).
 		Inputs(inputs).
 		FlagWithOutput("> ", m.outputPath)
diff --git a/definitions.mk b/definitions.mk
index 16c8bd6..1a7d06e 100644
--- a/definitions.mk
+++ b/definitions.mk
@@ -2,7 +2,7 @@
 # processed by checkpolicy
 define transform-policy-to-conf
 @mkdir -p $(dir $@)
-$(hide) m4 --fatal-warnings $(PRIVATE_ADDITIONAL_M4DEFS) \
+$(hide) $(M4) --fatal-warnings $(PRIVATE_ADDITIONAL_M4DEFS) \
 	-D mls_num_sens=$(PRIVATE_MLS_SENS) -D mls_num_cats=$(PRIVATE_MLS_CATS) \
 	-D target_build_variant=$(PRIVATE_TARGET_BUILD_VARIANT) \
 	-D target_with_dexpreopt=$(WITH_DEXPREOPT) \
@@ -13,6 +13,6 @@
 	-D target_compatible_property=$(PRIVATE_COMPATIBLE_PROPERTY) \
 	-D target_exclude_build_test=$(PRIVATE_EXCLUDE_BUILD_TEST) \
 	$(PRIVATE_TGT_RECOVERY) \
-	-s $^ > $@
+	-s $(PRIVATE_POLICY_FILES) > $@
 endef
 .KATI_READONLY := transform-policy-to-conf
diff --git a/mac_permissions.mk b/mac_permissions.mk
index 86ea9ab..7cb1b98 100644
--- a/mac_permissions.mk
+++ b/mac_permissions.mk
@@ -7,14 +7,16 @@
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
+all_plat_mac_perms_keys := $(call build_policy, keys.conf, $(PLAT_PRIVATE_POLICY) $(PRODUCT_PRIVATE_POLICY))
+all_plat_mac_perms_files := $(call build_policy, mac_permissions.xml, $(PLAT_PRIVATE_POLICY))
+
 # Build keys.conf
 plat_mac_perms_keys.tmp := $(intermediates)/plat_keys.tmp
 $(plat_mac_perms_keys.tmp): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
-$(plat_mac_perms_keys.tmp): $(call build_policy, keys.conf, $(PLAT_PRIVATE_POLICY) $(PRODUCT_PRIVATE_POLICY))
+$(plat_mac_perms_keys.tmp): PRIVATE_KEYS := $(all_plat_mac_perms_keys)
+$(plat_mac_perms_keys.tmp): $(all_plat_mac_perms_keys) $(M4)
 	@mkdir -p $(dir $@)
-	$(hide) m4 --fatal-warnings -s $(PRIVATE_ADDITIONAL_M4DEFS) $^ > $@
-
-all_plat_mac_perms_files := $(call build_policy, mac_permissions.xml, $(PLAT_PRIVATE_POLICY))
+	$(hide) $(M4) --fatal-warnings -s $(PRIVATE_ADDITIONAL_M4DEFS) $(PRIVATE_KEYS) > $@
 
 # Should be synced with keys.conf.
 all_plat_keys := platform media networkstack shared testkey
@@ -27,8 +29,9 @@
 	$(hide) DEFAULT_SYSTEM_DEV_CERTIFICATE="$(dir $(DEFAULT_SYSTEM_DEV_CERTIFICATE))" \
 		$(HOST_OUT_EXECUTABLES)/insertkeys.py -t $(TARGET_BUILD_VARIANT) -c $(TOP) $< -o $@ $(PRIVATE_MAC_PERMS_FILES)
 
-all_mac_perms_files :=
 all_plat_keys :=
+all_plat_mac_perms_files :=
+all_plat_mac_perms_keys :=
 plat_mac_perms_keys.tmp :=
 
 ##################################
@@ -41,14 +44,16 @@
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
+all_product_mac_perms_keys := $(call build_policy, keys.conf, $(PRODUCT_PRIVATE_POLICY) $(REQD_MASK_POLICY))
+all_product_mac_perms_files := $(call build_policy, mac_permissions.xml, $(PRODUCT_PRIVATE_POLICY) $(REQD_MASK_POLICY))
+
 # Build keys.conf
 product_mac_perms_keys.tmp := $(intermediates)/product_keys.tmp
 $(product_mac_perms_keys.tmp): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
-$(product_mac_perms_keys.tmp): $(call build_policy, keys.conf, $(PRODUCT_PRIVATE_POLICY) $(REQD_MASK_POLICY))
+$(product_mac_perms_keys.tmp): PRIVATE_KEYS := $(all_product_mac_perms_keys)
+$(product_mac_perms_keys.tmp): $(all_product_mac_perms_keys)
 	@mkdir -p $(dir $@)
-	$(hide) m4 --fatal-warnings -s $(PRIVATE_ADDITIONAL_M4DEFS) $^ > $@
-
-all_product_mac_perms_files := $(call build_policy, mac_permissions.xml, $(PRODUCT_PRIVATE_POLICY) $(REQD_MASK_POLICY))
+	$(hide) $(M4) --fatal-warnings -s $(PRIVATE_ADDITIONAL_M4DEFS) $^ > $@
 
 $(LOCAL_BUILT_MODULE): PRIVATE_MAC_PERMS_FILES := $(all_product_mac_perms_files)
 $(LOCAL_BUILT_MODULE): $(product_mac_perms_keys.tmp) $(HOST_OUT_EXECUTABLES)/insertkeys.py \
@@ -58,6 +63,7 @@
 
 product_mac_perms_keys.tmp :=
 all_product_mac_perms_files :=
+all_product_mac_perms_keys :=
 
 ##################################
 include $(CLEAR_VARS)
@@ -69,14 +75,16 @@
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
+all_vendor_mac_perms_keys := $(call build_policy, keys.conf, $(PLAT_VENDOR_POLICY) $(BOARD_VENDOR_SEPOLICY_DIRS) $(REQD_MASK_POLICY))
+all_vendor_mac_perms_files := $(call build_policy, mac_permissions.xml, $(PLAT_VENDOR_POLICY) $(BOARD_VENDOR_SEPOLICY_DIRS) $(REQD_MASK_POLICY))
+
 # Build keys.conf
 vendor_mac_perms_keys.tmp := $(intermediates)/vendor_keys.tmp
 $(vendor_mac_perms_keys.tmp): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
-$(vendor_mac_perms_keys.tmp): $(call build_policy, keys.conf, $(PLAT_VENDOR_POLICY) $(BOARD_VENDOR_SEPOLICY_DIRS) $(REQD_MASK_POLICY))
+$(vendor_mac_perms_keys.tmp): PRIVATE_KEYS := $(all_vendor_mac_perms_keys)
+$(vendor_mac_perms_keys.tmp): $(all_vendor_mac_perms_keys) $(M4)
 	@mkdir -p $(dir $@)
-	$(hide) m4 --fatal-warnings -s $(PRIVATE_ADDITIONAL_M4DEFS) $^ > $@
-
-all_vendor_mac_perms_files := $(call build_policy, mac_permissions.xml, $(PLAT_VENDOR_POLICY) $(BOARD_VENDOR_SEPOLICY_DIRS) $(REQD_MASK_POLICY))
+	$(hide) $(M4) --fatal-warnings -s $(PRIVATE_ADDITIONAL_M4DEFS) $(PRIVATE_KEYS) > $@
 
 $(LOCAL_BUILT_MODULE): PRIVATE_MAC_PERMS_FILES := $(all_vendor_mac_perms_files)
 $(LOCAL_BUILT_MODULE): $(vendor_mac_perms_keys.tmp) $(HOST_OUT_EXECUTABLES)/insertkeys.py \
@@ -86,6 +94,7 @@
 
 vendor_mac_perms_keys.tmp :=
 all_vendor_mac_perms_files :=
+all_vendor_mac_perms_keys :=
 
 ##################################
 include $(CLEAR_VARS)
@@ -97,14 +106,16 @@
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
+all_odm_mac_perms_keys := $(call build_policy, keys.conf, $(BOARD_ODM_SEPOLICY_DIRS) $(REQD_MASK_POLICY))
+all_odm_mac_perms_files := $(call build_policy, mac_permissions.xml, $(BOARD_ODM_SEPOLICY_DIRS) $(REQD_MASK_POLICY))
+
 # Build keys.conf
 odm_mac_perms_keys.tmp := $(intermediates)/odm_keys.tmp
 $(odm_mac_perms_keys.tmp): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
-$(odm_mac_perms_keys.tmp): $(call build_policy, keys.conf, $(BOARD_ODM_SEPOLICY_DIRS) $(REQD_MASK_POLICY))
+$(odm_mac_perms_keys.tmp): PRIVATE_KEYS := $(all_odm_mac_perms_keys)
+$(odm_mac_perms_keys.tmp): $(all_odm_mac_perms_keys) $(M4)
 	@mkdir -p $(dir $@)
-	$(hide) m4 --fatal-warnings -s $(PRIVATE_ADDITIONAL_M4DEFS) $^ > $@
-
-all_odm_mac_perms_files := $(call build_policy, mac_permissions.xml, $(BOARD_ODM_SEPOLICY_DIRS) $(REQD_MASK_POLICY))
+	$(hide) $(M4) --fatal-warnings -s $(PRIVATE_ADDITIONAL_M4DEFS) $(PRIVATE_KEYS) > $@
 
 $(LOCAL_BUILT_MODULE): PRIVATE_MAC_PERMS_FILES := $(all_odm_mac_perms_files)
 $(LOCAL_BUILT_MODULE): $(odm_mac_perms_keys.tmp) $(HOST_OUT_EXECUTABLES)/insertkeys.py \
diff --git a/treble_sepolicy_tests_for_release.mk b/treble_sepolicy_tests_for_release.mk
index 40e75c0..3d9bca4 100644
--- a/treble_sepolicy_tests_for_release.mk
+++ b/treble_sepolicy_tests_for_release.mk
@@ -16,6 +16,7 @@
 # been maintained by our mapping files.
 $(version)_PLAT_PUBLIC_POLICY := $(LOCAL_PATH)/prebuilts/api/$(version)/public
 $(version)_PLAT_PRIVATE_POLICY := $(LOCAL_PATH)/prebuilts/api/$(version)/private
+policy_files := $(call build_policy, $(sepolicy_build_files), $($(version)_PLAT_PUBLIC_POLICY) $($(version)_PLAT_PRIVATE_POLICY))
 $(version)_plat_policy.conf := $(intermediates)/$(version)_plat_policy.conf
 $($(version)_plat_policy.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
 $($(version)_plat_policy.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
@@ -25,11 +26,12 @@
 $($(version)_plat_policy.conf): PRIVATE_TGT_WITH_NATIVE_COVERAGE := $(with_native_coverage)
 $($(version)_plat_policy.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
 $($(version)_plat_policy.conf): PRIVATE_SEPOLICY_SPLIT := true
-$($(version)_plat_policy.conf): $(call build_policy, $(sepolicy_build_files), \
-$($(version)_PLAT_PUBLIC_POLICY) $($(version)_PLAT_PRIVATE_POLICY))
+$($(version)_plat_policy.conf): PRIVATE_POLICY_FILES := $(policy_files)
+$($(version)_plat_policy.conf): $(policy_files) $(M4)
 	$(transform-policy-to-conf)
 	$(hide) sed '/dontaudit/d' $@ > $@.dontaudit
 
+policy_files :=
 
 built_$(version)_plat_sepolicy := $(intermediates)/built_$(version)_plat_sepolicy
 $(built_$(version)_plat_sepolicy): PRIVATE_ADDITIONAL_CIL_FILES := \