new file mode 100644
--- /dev/null
+++ b/build/macosx/check-sync-exceptions
@@ -0,0 +1,4 @@
+# Install OSX Bug 1400533
+# Until we are cross-building OSX or the OS on the build workers are updated,
+# we need to use a newer SDK than the installed SDK.
+local-mozconfig.common

new file mode 100644
--- /dev/null
+++ b/mail/config/tooltool-manifests/macosx64/check-sync-exceptions
@@ -0,0 +1,5 @@
+# Install OSX Bug 1400533
+# Until we are cross-building OSX or the OS on the build workers are updated,
+# we need to use a newer SDK than the installed SDK.
+clang.manifest
+releng.manifest