soong: Add ability to build scudo-free 32-bit libc variant.

Targets can switch on this feature by setting
MALLOC_SVELTE_FOR_LIBC32 := true

The default is to build libc32 with scudo enabled.

Change-Id: I207659af05412a8e7dc850d57b491ee565554a65

core/soong_config.mk

@@ -139,6 +139,9 @@ $(call add_json_bool, BoardVndkRuntimeDisable,           $(BOARD_VNDK_RUNTIME_DI
 $(call add_json_list, DeviceSystemSdkVersions,           $(BOARD_SYSTEMSDK_VERSIONS))
 $(call add_json_list, Platform_systemsdk_versions,       $(PLATFORM_SYSTEMSDK_VERSIONS))
 $(call add_json_bool, Malloc_not_svelte,                 $(call invert_bool,$(filter true,$(MALLOC_SVELTE))))
+$(call add_json_bool, Malloc_not_svelte_libc32,          $(if $(MALLOC_SVELTE_FOR_LIBC32),\
+                                                            $(call invert_bool,$(filter true,$(MALLOC_SVELTE_FOR_LIBC32))),\
+                                                            $(call invert_bool,$(filter true,$(MALLOC_SVELTE)))))
 $(call add_json_str,  Override_rs_driver,                $(OVERRIDE_RS_DRIVER))
 
 $(call add_json_bool, UncompressPrivAppDex,              $(call invert_bool,$(filter true,$(DONT_UNCOMPRESS_PRIV_APPS_DEXS))))