copy from browser/config/mozconfigs/macosx-universal/beta
copy to browser/config/mozconfigs/macosx64/beta
--- a/browser/config/mozconfigs/macosx-universal/beta
+++ b/browser/config/mozconfigs/macosx64/beta
@@ -1,15 +1,15 @@
 MOZ_AUTOMATION_SDK=${MOZ_AUTOMATION_SDK-1}
 
 if [ -n "$ENABLE_RELEASE_PROMOTION" ]; then
   MOZ_AUTOMATION_UPLOAD_SYMBOLS=1
   MOZ_AUTOMATION_UPDATE_PACKAGING=1
 fi
 
-. "$topsrcdir/browser/config/mozconfigs/macosx-universal/common-opt"
+. "$topsrcdir/browser/config/mozconfigs/macosx64/common-opt"
 
 ac_add_options --enable-official-branding
 ac_add_options --enable-verify-mar
 
 . "$topsrcdir/build/mozconfig.rust"
 . "$topsrcdir/build/mozconfig.common.override"
 . "$topsrcdir/build/mozconfig.cache"

copy from browser/config/mozconfigs/macosx-universal/common-opt
copy to browser/config/mozconfigs/macosx64/common-opt
--- a/browser/config/mozconfigs/macosx-universal/common-opt
+++ b/browser/config/mozconfigs/macosx64/common-opt
@@ -1,14 +1,11 @@
 # This file is sourced by the nightly, beta, and release mozconfigs.
 
-. $topsrcdir/build/macosx/universal/mozconfig
-
-# Universal builds override the default of browser (bug 575283 comment 29)
-ac_add_options --enable-application=browser
+. $topsrcdir/build/macosx/mozconfig.common
 
 ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
 ac_add_options --with-google-api-keyfile=/builds/gapi.data
 ac_add_options --with-mozilla-api-keyfile=/builds/mozilla-desktop-geoloc-api.key
 
 # Needed to enable breakpad in application.ini
 export MOZILLA_OFFICIAL=1
 

--- a/browser/config/mozconfigs/macosx64/nightly
+++ b/browser/config/mozconfigs/macosx64/nightly
@@ -1,22 +1,21 @@
-. $topsrcdir/build/macosx/mozconfig.common
-
-ac_add_options --enable-verify-mar
+. "$topsrcdir/browser/config/mozconfigs/macosx64/common-opt"
 
-# Needed to enable breakpad in application.ini
-export MOZILLA_OFFICIAL=1
+ac_add_options --disable-install-strip
+ac_add_options --enable-verify-mar
+ac_add_options --enable-profiling
+ac_add_options --enable-instruments
 
-# Enable Telemetry
-export MOZ_TELEMETRY_REPORTING=1
+# Cross-compiled builds fail when dtrace is enabled
+if test `uname -s` != Linux; then
+  ac_add_options --enable-dtrace
+fi
 
 if test "${MOZ_UPDATE_CHANNEL}" = "nightly"; then
 ac_add_options --with-macbundlename-prefix=Firefox
 fi
 
-# Package js shell.
-export MOZ_PACKAGE_JSSHELL=1
-
 ac_add_options --with-branding=browser/branding/nightly
 
 . "$topsrcdir/build/mozconfig.rust"
 . "$topsrcdir/build/mozconfig.common.override"
 . "$topsrcdir/build/mozconfig.cache"

copy from browser/config/mozconfigs/macosx-universal/release
copy to browser/config/mozconfigs/macosx64/release
--- a/browser/config/mozconfigs/macosx-universal/release
+++ b/browser/config/mozconfigs/macosx64/release
@@ -2,17 +2,17 @@
 # safeguard below
 MOZ_AUTOMATION_SDK=${MOZ_AUTOMATION_SDK-1}
 
 if [ -n "$ENABLE_RELEASE_PROMOTION" ]; then
   MOZ_AUTOMATION_UPLOAD_SYMBOLS=1
   MOZ_AUTOMATION_UPDATE_PACKAGING=1
 fi
 
-. "$topsrcdir/browser/config/mozconfigs/macosx-universal/common-opt"
+. "$topsrcdir/browser/config/mozconfigs/macosx64/common-opt"
 
 ac_add_options --enable-official-branding
 ac_add_options --enable-verify-mar
 
 # safeguard against someone forgetting to re-set EARLY_BETA_OR_EARLIER in
 # defines.sh during the beta cycle
 export BUILDING_RELEASE=1
 

--- a/browser/config/mozconfigs/whitelist
+++ b/browser/config/mozconfigs/whitelist
@@ -1,26 +1,26 @@
 # 'nightly' contains things that are in nightly mozconfigs and allowed to be missing from release builds.
 # Other keys in whitelist contain things are in that branches mozconfigs and allowed to be missing from nightly builds.
 whitelist = {
     'release': {},
     'nightly': {},
     }
 
-all_platforms = ['win64', 'win32', 'linux32', 'linux64', 'macosx-universal']
+all_platforms = ['win64', 'win32', 'linux32', 'linux64', 'macosx64']
 
 for platform in all_platforms:
     whitelist['nightly'][platform] = [
         'ac_add_options --enable-update-channel=nightly',
         'ac_add_options --with-branding=browser/branding/nightly',
         'ac_add_options --enable-profiling',
         'mk_add_options CLIENT_PY_ARGS="--hg-options=\'--verbose --time\' --hgtool=../tools/buildfarm/utils/hgtool.py --skip-chatzilla --skip-comm --skip-inspector --tinderbox-print"'
     ]
 
-for platform in ['linux32', 'linux64', 'macosx-universal']:
+for platform in ['linux32', 'linux64', 'macosx64']:
     whitelist['nightly'][platform] += [
         'mk_add_options MOZ_MAKE_FLAGS="-j4"',
     ]
 
 whitelist['nightly']['linux32'] += [
     'CXX=$REAL_CXX',
     'CXX="ccache $REAL_CXX"',
     'CC="ccache $REAL_CC"',
@@ -37,17 +37,17 @@ whitelist['nightly']['linux64'] += [
     'export MOZILLA_OFFICIAL=1',
     'export MOZ_TELEMETRY_REPORTING=1',
     "mk_add_options PROFILE_GEN_SCRIPT='$(PYTHON) @MOZ_OBJDIR@/_profile/pgo/profileserver.py 10'",
     'STRIP_FLAGS="--strip-debug"',
     'ac_add_options --with-ccache=/usr/bin/ccache',
     '. "$topsrcdir/build/mozconfig.cache"',
 ]
 
-whitelist['nightly']['macosx-universal'] += [
+whitelist['nightly']['macosx64'] += [
     'if test "${MOZ_UPDATE_CHANNEL}" = "nightly"; then',
     'ac_add_options --with-macbundlename-prefix=Firefox',
     'fi',
     'mk_add_options MOZ_MAKE_FLAGS="-j12"',
     'ac_add_options --with-ccache',
     '. "$topsrcdir/build/mozconfig.cache"',
     'ac_add_options --disable-install-strip',
     'ac_add_options --enable-instruments',

--- a/build/compare-mozconfig/compare-mozconfigs-wrapper.py
+++ b/build/compare-mozconfig/compare-mozconfigs-wrapper.py
@@ -14,18 +14,17 @@ import unittest
 from os import path
 from buildconfig import substs
 
 log = logging.getLogger(__name__)
 
 def determine_platform():
     platform_mapping = {'WINNT': {'x86_64': 'win64',
                                   'i686': 'win32'},
-                        'Darwin': {'x86_64': 'macosx-universal',
-                                   'i386':'macosx-universal'},
+                        'Darwin': {'x86_64': 'macosx64'},
                         'Linux': {'x86_64': 'linux64',
                                   'i686': 'linux32'}}
 
     os_type = substs['OS_TARGET']
     cpu_type = substs['TARGET_CPU']
     return platform_mapping.get(os_type, {}).get(cpu_type, None)
 
 

--- a/taskcluster/ci/build/macosx.yml
+++ b/taskcluster/ci/build/macosx.yml
@@ -39,32 +39,8 @@ macosx64/opt:
         using: mozharness
         actions: [get-secrets build generate-build-stats update]
         config:
             - builds/releng_base_mac_64_cross_builds.py
             - balrog/production.py
         script: "mozharness/scripts/fx_desktop_build.py"
         secrets: true
         tooltool-downloads: internal
-
-macosx64-universal/opt:
-    description: "MacOS X Universal Cross-compile"
-    index:
-        product: firefox
-        job-name: macosx64-opt
-    treeherder:
-        platform: osx-10-7/opt
-        symbol: tc(Bu)
-        tier: 2
-    worker-type: aws-provisioner-v1/gecko-{level}-b-macosx64
-    worker:
-        implementation: docker-worker
-        max-run-time: 36000
-    run:
-        using: mozharness
-        actions: [get-secrets build generate-build-stats update]
-        config:
-            - builds/releng_base_mac_64_cross_builds.py
-            - balrog/production.py
-        script: "mozharness/scripts/fx_desktop_build.py"
-        secrets: true
-        custom-build-variant-cfg: cross-universal
-        tooltool-downloads: internal

--- a/testing/mozharness/configs/builds/branch_specifics.py
+++ b/testing/mozharness/configs/builds/branch_specifics.py
@@ -47,17 +47,17 @@ config = {
                 'src_mozconfig': 'browser/config/mozconfigs/linux32/release',
                 'force_clobber': True,
             },
             'linux64': {
                 'src_mozconfig': 'browser/config/mozconfigs/linux64/release',
                 'force_clobber': True,
             },
             'macosx64': {
-                'src_mozconfig': 'browser/config/mozconfigs/macosx-universal/release',
+                'src_mozconfig': 'browser/config/mozconfigs/macosx64/release',
                 'force_clobber': True,
             },
             'win32': {
                 'src_mozconfig': 'browser/config/mozconfigs/win32/release',
                 'force_clobber': True,
             },
             'win64': {
                 'src_mozconfig': 'browser/config/mozconfigs/win64/release',
@@ -121,17 +121,17 @@ config = {
                 'src_mozconfig': 'browser/config/mozconfigs/linux32/beta',
                 'force_clobber': True,
             },
             'linux64': {
                 'src_mozconfig': 'browser/config/mozconfigs/linux64/beta',
                 'force_clobber': True,
             },
             'macosx64': {
-                'src_mozconfig': 'browser/config/mozconfigs/macosx-universal/beta',
+                'src_mozconfig': 'browser/config/mozconfigs/macosx64/beta',
                 'force_clobber': True,
             },
             'win32': {
                 'src_mozconfig': 'browser/config/mozconfigs/win32/beta',
                 'force_clobber': True,
             },
             'win64': {
                 'src_mozconfig': 'browser/config/mozconfigs/win64/beta',

--- a/testing/mozharness/configs/builds/releng_base_mac_64_builds.py
+++ b/testing/mozharness/configs/builds/releng_base_mac_64_builds.py
@@ -22,17 +22,17 @@ config = {
         'python2.7': sys.executable,
         "buildbot": "/tools/buildbot/bin/buildbot",
     },
     'app_ini_path': '%(obj_dir)s/dist/bin/application.ini',
     # decides whether we want to use moz_sign_cmd in env
     'enable_signing': True,
     'enable_ccache': True,
     'vcs_share_base': '/builds/hg-shared',
-    'objdir': 'obj-firefox/x86_64',
+    'objdir': 'obj-firefox',
     'tooltool_script': ["/builds/tooltool.py"],
     'tooltool_bootstrap': "setup.sh",
     'enable_count_ctors': False,
     'enable_talos_sendchange': True,
     'enable_unittest_sendchange': True,
     #########################################################################
 
 
@@ -68,12 +68,12 @@ config = {
         'UPLOAD_USER': '%(stage_username)s',
         'UPLOAD_SSH_KEY': '/Users/cltbld/.ssh/%(stage_ssh_key)s',
         'UPLOAD_TO_TEMP': '1',
     },
     "check_test_env": {
         'MINIDUMP_STACKWALK': '%(abs_tools_dir)s/breakpad/osx64/minidump_stackwalk',
         'MINIDUMP_SAVE_PATH': '%(base_work_dir)s/minidumps',
     },
-    'src_mozconfig': 'browser/config/mozconfigs/macosx-universal/nightly',
+    'src_mozconfig': 'browser/config/mozconfigs/macosx64/nightly',
     'tooltool_manifest_src': 'browser/config/tooltool-manifests/macosx64/releng.manifest',
     #########################################################################
 }

--- a/testing/mozharness/configs/merge_day/aurora_to_beta.py
+++ b/testing/mozharness/configs/merge_day/aurora_to_beta.py
@@ -31,20 +31,19 @@ config = {
     ] + [
         # File, from, to
         (f, "ac_add_options --with-branding=browser/branding/aurora",
          "ac_add_options --enable-official-branding")
         for f in ["browser/config/mozconfigs/linux32/l10n-mozconfig",
                   "browser/config/mozconfigs/linux64/l10n-mozconfig",
                   "browser/config/mozconfigs/win32/l10n-mozconfig",
                   "browser/config/mozconfigs/win64/l10n-mozconfig",
-                  "browser/config/mozconfigs/macosx-universal/l10n-mozconfig",
                   "browser/config/mozconfigs/macosx64/l10n-mozconfig"]
     ] + [
-        ("browser/config/mozconfigs/macosx-universal/nightly",
+        ("browser/config/mozconfigs/macosx64/nightly",
          "ac_add_options --with-branding=browser/branding/aurora",
          "ac_add_options --with-branding=browser/branding/nightly"),
         ("browser/confvars.sh",
          "ACCEPTED_MAR_CHANNEL_IDS=firefox-mozilla-aurora",
          "ACCEPTED_MAR_CHANNEL_IDS=firefox-mozilla-beta,firefox-mozilla-release"),
         ("browser/confvars.sh",
          "MAR_CHANNEL_ID=firefox-mozilla-aurora",
          "MAR_CHANNEL_ID=firefox-mozilla-beta"),

--- a/testing/mozharness/configs/merge_day/central_to_aurora.py
+++ b/testing/mozharness/configs/merge_day/central_to_aurora.py
@@ -36,31 +36,31 @@ config = {
                   "mobile/android/config/mozconfigs/android-x86/"]
     ] + [
         # File, from, to
         (f, "ac_add_options --enable-profiling", "") for f in
         ["mobile/android/config/mozconfigs/android-api-15/nightly",
          "mobile/android/config/mozconfigs/android-x86/nightly",
          "browser/config/mozconfigs/linux32/nightly",
          "browser/config/mozconfigs/linux64/nightly",
-         "browser/config/mozconfigs/macosx-universal/nightly",
+         "browser/config/mozconfigs/macosx64/nightly",
          "browser/config/mozconfigs/win32/nightly",
          "browser/config/mozconfigs/win64/nightly"]
     ] + [
         # File, from, to
         ("browser/confvars.sh",
          "ACCEPTED_MAR_CHANNEL_IDS=firefox-mozilla-central",
          "ACCEPTED_MAR_CHANNEL_IDS=firefox-mozilla-aurora"),
         ("browser/confvars.sh",
          "MAR_CHANNEL_ID=firefox-mozilla-central",
          "MAR_CHANNEL_ID=firefox-mozilla-aurora"),
-        ("browser/config/mozconfigs/macosx-universal/nightly",
+        ("browser/config/mozconfigs/macosx64/nightly",
          "ac_add_options --with-branding=browser/branding/nightly",
          "ac_add_options --with-branding=browser/branding/aurora"),
-        ("browser/config/mozconfigs/macosx-universal/l10n-mozconfig",
+        ("browser/config/mozconfigs/macosx64/l10n-mozconfig",
          "ac_add_options --with-branding=browser/branding/nightly",
          "ac_add_options --with-branding=browser/branding/aurora"),
         ("browser/config/mozconfigs/whitelist",
          "ac_add_options --with-branding=browser/branding/nightly",
          "ac_add_options --with-branding=browser/branding/aurora"),
     ],
     "locale_files": [
         "browser/locales/shipped-locales",

--- a/testing/mozharness/configs/single_locale/macosx64.py
+++ b/testing/mozharness/configs/single_locale/macosx64.py
@@ -1,16 +1,16 @@
 import os
 
 config = {
     # mozconfig file to use, it depends on branch and platform names
     "platform": "macosx64",
     "stage_product": "firefox",
     "update_platform": "Darwin_x86_64-gcc3",
-    "mozconfig": "%(branch)s/browser/config/mozconfigs/macosx-universal/l10n-mozconfig",
+    "mozconfig": "%(branch)s/browser/config/mozconfigs/macosx64/l10n-mozconfig",
     "bootstrap_env": {
         "SHELL": '/bin/bash',
         "MOZ_OBJDIR": "obj-l10n",
         "EN_US_BINARY_URL": "%(en_us_binary_url)s",
         "MOZ_UPDATE_CHANNEL": "%(update_channel)s",
         "MOZ_PKG_PLATFORM": "mac",
         # "IS_NIGHTLY": "yes",
         "DIST": "%(abs_objdir)s",

--- a/testing/web-platform/meta/encrypted-media/clearkey-mp4-playback-temporary-encrypted-clear.html.ini
+++ b/testing/web-platform/meta/encrypted-media/clearkey-mp4-playback-temporary-encrypted-clear.html.ini
@@ -1,20 +1,20 @@
 [clearkey-mp4-playback-temporary-encrypted-clear.html]
   type: testharness
   expected:
-    if not debug and not e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86") and (bits == 32): TIMEOUT
-    if not debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86") and (bits == 32): TIMEOUT
+    if not debug and not e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT
+    if not debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT
     if debug and not e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT
     if debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT
   [org.w3.clearkey, temporary, mp4, playback, single key, encrypted then clear content]
     expected:
       if not debug and e10s and (os == "win") and (version == "5.1.2600") and (processor == "x86") and (bits == 32): FAIL
       if debug and not e10s and (os == "win") and (version == "5.1.2600") and (processor == "x86") and (bits == 32): FAIL
       if debug and e10s and (os == "win") and (version == "5.1.2600") and (processor == "x86") and (bits == 32): FAIL
       if not debug and not e10s and (os == "win") and (version == "5.1.2600") and (processor == "x86") and (bits == 32): FAIL
-      if not debug and not e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86") and (bits == 32): TIMEOUT
-      if not debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86") and (bits == 32): TIMEOUT
+      if not debug and not e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT
+      if not debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT
       if debug and not e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT
       if debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT
       if not debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT
       if not debug and not e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT
 

--- a/testing/web-platform/meta/encrypted-media/clearkey-mp4-setmediakeys.html.ini
+++ b/testing/web-platform/meta/encrypted-media/clearkey-mp4-setmediakeys.html.ini
@@ -1,4 +1,2 @@
 [clearkey-mp4-setmediakeys.html]
   type: testharness
-  expected:
-    if not debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT

--- a/testing/web-platform/meta/mathml/relations/css-styling/color-1.html.ini
+++ b/testing/web-platform/meta/mathml/relations/css-styling/color-1.html.ini
@@ -1,12 +1,12 @@
 [color-1.html]
   type: reftest
   expected:
-    if not debug and not e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86") and (bits == 32): PASS
-    if not debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86") and (bits == 32): PASS
+    if not debug and not e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): PASS
+    if not debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): PASS
     if debug and not e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): PASS
     if debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): PASS
     if not debug and e10s and (os == "win") and (version == "5.1.2600") and (processor == "x86") and (bits == 32): PASS
     if debug and not e10s and (os == "win") and (version == "5.1.2600") and (processor == "x86") and (bits == 32): PASS
     if debug and e10s and (os == "win") and (version == "5.1.2600") and (processor == "x86") and (bits == 32): PASS
     if not debug and not e10s and (os == "win") and (version == "5.1.2600") and (processor == "x86") and (bits == 32): PASS
     FAIL