Building Qt Creator master with qbs master fails

qbs -d ../qtcreator_qbs_debug_build
No build graph exists yet for this configuration.
Resolving project for configuration qt56debug-debug
WARNING: qbs.getEnv is deprecated and will be removed in Qbs 1.6. Use Environment.getEnv instead.
WARNING: qbs.getEnv is deprecated and will be removed in Qbs 1.6. Use Environment.getEnv instead.
.... (lots of env warnings)

ERROR: /Users/alex/Dev/qt/qt57_source/qbs/qbs/share/qbs/modules/xcode/xcode.qbs:98:58 TypeError: Result of expression 'Utils.findSigningIdentities' [undefined] is not a function.