When the ECMAScript Internationalization API is enabled in all main Mozilla products, the ability to build SpiderMonkey without support for ECMA-402 should be removed. Steps: - Remove all definitions for --enable-intl-api from mozconfig files. - Remove the tests for the --enable-intl-api flag from configure.in and js/src/configure.in files, and update the files as if it was always set. - Remove the tests for the ENABLE_INTL_API variable from js/src/configure.in and js/src/Makefile.in, and update the files as if it was always set. - Remove the tests for the ENABLE_INTL_API flag from .h and .cpp files in js/src, and remove code that depends on it being undefined or 0. - Change the return type of InitRuntimeNumberState as indicated by a comment in jsnum.cpp. - Remove the localeCompare member from JSLocaleCallbacks in jsapi.h, and the code setting it and the Compare function from js/xpconnect/src/XPCLocale.cpp. - Remove the skip-if(!this.hasOwnProperty("Intl")) conditions from js/src/tests/jstests.list and the tests within js/src/tests/Intl.

As per bug 1402235 - there's a request to preserve the ability to build without ICU for special purposes. I'm going to WONTFIX this and if we'll ever get back to the idea, we'll file a new issue.