Expose Treble requirement variables in Soong.

As a followup to this, Treble will be removed. It's too generic
to be used with any reliability or meaning. Individual switches
also mean that they can be used independently.

Bug: 62019611
Test: manual
Change-Id: Ib1bd7d23510daac70a4520b9082f7492b8cbf027
diff --git a/core/soong_config.mk b/core/soong_config.mk
index f1f1e09..7f34cc5 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -115,7 +115,12 @@
 $(call add_json_list, ExtraVndkVersions,                 $(PRODUCT_EXTRA_VNDK_VERSIONS))
 $(call add_json_bool, Malloc_not_svelte,                 $(call invert_bool,$(filter true,$(MALLOC_SVELTE))))
 $(call add_json_str,  Override_rs_driver,                $(OVERRIDE_RS_DRIVER))
+
 $(call add_json_bool, Treble,                            $(filter true,$(PRODUCT_FULL_TREBLE)))
+$(call add_json_bool, Treble_linker_namespaces,          $(filter true,$(PRODUCT_TREBLE_LINKER_NAMESPACES)))
+$(call add_json_bool, Sepolicy_split,                    $(filter true,$(PRODUCT_SEPOLICY_SPLIT)))
+$(call add_json_bool, Enforce_vintf_manifest,            $(filter true,$(PRODUCT_ENFORCE_VINTF_MANIFEST)))
+
 $(call add_json_bool, Uml,                               $(filter true,$(TARGET_USER_MODE_LINUX)))
 $(call add_json_str,  VendorPath,                        $(TARGET_COPY_OUT_VENDOR))
 $(call add_json_bool, MinimizeJavaDebugInfo,             $(filter true,$(PRODUCT_MINIMIZE_JAVA_DEBUG_INFO)))