--- a/build/autoconf/icu.m4
+++ b/build/autoconf/icu.m4
@@ -46,24 +46,30 @@ yes)
     ENABLE_INTL_API=1
     EXPOSE_INTL_API=1
     ;;
 *)
     AC_MSG_ERROR([Invalid value passed to --with-intl-api: $_INTL_API])
     ;;
 esac
 
+if test -n "$ENABLE_INTL_API"; then
+    USE_ICU=1
+fi
+
 if test -n "$EXPOSE_INTL_API"; then
     AC_DEFINE(EXPOSE_INTL_API)
 fi
 
-dnl Settings for the implementation of the ECMAScript Internationalization API
 if test -n "$ENABLE_INTL_API"; then
     AC_DEFINE(ENABLE_INTL_API)
+fi
 
+dnl Settings for the implementation of the ECMAScript Internationalization API
+if test -n "$USE_ICU"; then
     icudir="$_topsrcdir/intl/icu/source"
     if test ! -d "$icudir"; then
         icudir="$_topsrcdir/../../intl/icu/source"
         if test ! -d "$icudir"; then
             AC_MSG_ERROR([Cannot find the ICU directory])
         fi
     fi
 
@@ -95,36 +101,37 @@ if test -n "$ENABLE_INTL_API"; then
             *)
                 AC_MSG_ERROR([ECMAScript Internationalization API is not yet supported on this platform])
         esac
     fi
 fi
 
 AC_SUBST(MOZ_ICU_DBG_SUFFIX)
 AC_SUBST(ENABLE_INTL_API)
+AC_SUBST(USE_ICU)
 AC_SUBST_LIST(ICU_LIB_NAMES)
 
-if test -n "$ENABLE_INTL_API" -a -z "$MOZ_NATIVE_ICU"; then
+if test -n "$USE_ICU" -a -z "$MOZ_NATIVE_ICU"; then
     dnl We build ICU as a static library for non-shared js builds and as a shared library for shared js builds.
     if test -z "$MOZ_SHARED_ICU"; then
         AC_DEFINE(U_STATIC_IMPLEMENTATION)
     fi
     dnl Source files that use ICU should have control over which parts of the ICU
     dnl namespace they want to use.
     AC_DEFINE(U_USING_ICU_NAMESPACE,0)
 fi
 
 
 ])
 
 AC_DEFUN([MOZ_SUBCONFIGURE_ICU], [
 
 if test -z "$BUILDING_JS" -o -n "$JS_STANDALONE"; then
 
-    if test -n "$ENABLE_INTL_API" -a -z "$MOZ_NATIVE_ICU"; then
+    if test -n "$USE_ICU" -a -z "$MOZ_NATIVE_ICU"; then
         # Set ICU compile options
         ICU_CPPFLAGS=""
         # don't use icu namespace automatically in client code
         ICU_CPPFLAGS="$ICU_CPPFLAGS -DU_USING_ICU_NAMESPACE=0"
         # don't include obsolete header files
         ICU_CPPFLAGS="$ICU_CPPFLAGS -DU_NO_DEFAULT_INCLUDE_UTF_HEADERS=1"
         # remove chunks of the library that we don't need (yet)
         ICU_CPPFLAGS="$ICU_CPPFLAGS -DUCONFIG_NO_LEGACY_CONVERSION"

--- a/config/external/icu/Makefile.in
+++ b/config/external/icu/Makefile.in
@@ -1,14 +1,14 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 # Ensure that this happens before including rules.mk
-ifdef ENABLE_INTL_API
+ifdef USE_ICU
   ifndef MOZ_NATIVE_ICU
   # Library names: On Windows, ICU uses modified library names for static
   # and debug libraries.
     ifdef MOZ_SHARED_ICU
       ifeq ($(OS_ARCH),WINNT)
         ifdef JS_SHARED_LIBRARY
           ICU_FILES := $(foreach libname,$(ICU_LIB_NAMES),$(DEPTH)/intl/icu/target/lib/$(libname)$(MOZ_ICU_DBG_SUFFIX)$(MOZ_ICU_VERSION).dll)
         endif
@@ -31,21 +31,21 @@ ifdef ENABLE_INTL_API
       endif
     else # !MOZ_SHARED_ICU
       ifeq ($(OS_ARCH),WINNT)
         ICU_LIB_RENAME = $(foreach libname,$(ICU_LIB_NAMES),\
                              cp -p $(DEPTH)/intl/icu/target/lib/s$(libname)$(MOZ_ICU_DBG_SUFFIX).lib $(DEPTH)/intl/icu/target/lib/$(libname)$(MOZ_ICU_DBG_SUFFIX).lib;)
       endif
     endif # MOZ_SHARED_ICU
   endif # !MOZ_NATIVE_ICU
-endif # ENABLE_INTL_API
+endif # USE_ICU
 
 include $(topsrcdir)/config/rules.mk
 
-ifdef ENABLE_INTL_API
+ifdef USE_ICU
 ifndef MOZ_NATIVE_ICU
 target:: buildicu
 $(STATIC_LIBS): buildicu
 
 # - Force ICU to use the standard suffix for object files because expandlibs
 #   will discard all files with a non-standard suffix (bug 857450).
 # - Options for genrb: -k strict parsing; -R omit collation tailoring rules.
 buildicu::

--- a/configure.in
+++ b/configure.in
@@ -9013,29 +9013,27 @@ dnl ICU Support
 dnl ========================================================
 
 # Internationalization isn't built or exposed by default in non-desktop
 # builds.  Bugs to enable:
 #
 #   Android:  bug 864843
 #   B2G:      bug 866301
 
-if test "$MOZ_WIDGET_TOOLKIT" = "android"; then
+if test "$MOZ_WIDGET_TOOLKIT" = "android" ||
+   test "$MOZ_BUILD_APP" = "b2g"; then
     _INTL_API=no
-elif test "$MOZ_BUILD_APP" = "b2g"; then
-    if test "$MOZ_WIDGET_TOOLKIT" = "cocoa"; then
-        # nsCollationMacUC needs ICU
-        _INTL_API=yes
-    else
-        _INTL_API=no
-    fi
 else
     _INTL_API=yes
 fi
 
+if test "$MOZ_WIDGET_TOOLKIT" = "cocoa"; then
+    USE_ICU=1
+fi
+
 MOZ_CONFIG_ICU()
 
 if test -z "$JS_SHARED_LIBRARY"; then
   AC_DEFINE(MOZ_STATIC_JS)
 fi
 AC_SUBST(JS_SHARED_LIBRARY)
 
 MOZ_CREATE_CONFIG_STATUS()

--- a/moz.build
+++ b/moz.build
@@ -55,17 +55,17 @@ if CONFIG['COMPILE_ENVIRONMENT'] and not
     if not CONFIG['JS_STANDALONE']:
         DIRS += [
             'config/external',
             'config/external/nss',
         ]
 
     if CONFIG['BUILD_CTYPES']:
         DIRS += ['config/external/ffi']
-    if CONFIG['ENABLE_INTL_API']:
+    if CONFIG['USE_ICU']:
         DIRS += ['config/external/icu']
     DIRS += ['js/src']
 
 if not CONFIG['JS_STANDALONE']:
     # Bring in the configuration for the configured application.
     include('/' + CONFIG['MOZ_BUILD_APP'] + '/app.mozbuild')
 
 include('build/templates.mozbuild')

--- a/toolkit/library/moz.build
+++ b/toolkit/library/moz.build
@@ -120,17 +120,17 @@ USE_LIBS += [
     'gkmedias',
     'mozalloc',
     'nspr',
     'nss',
     'sqlite',
     'zlib',
 ]
 
-if CONFIG['ENABLE_INTL_API']:
+if CONFIG['USE_ICU']:
     USE_LIBS += [
         'icu',
     ]
 
 if CONFIG['MOZ_WIDGET_GTK'] and CONFIG['MOZ_ENABLE_GTK3']:
     USE_LIBS += [
         'mozgtk_stub',
     ]