--- a/toolkit/moz.configure
+++ b/toolkit/moz.configure
@@ -665,19 +665,21 @@ def stylo(stylo_enabled, bindgen_config_
 
 set_config('MOZ_STYLO', delayed_getattr(stylo, 'enabled'))
 set_define('MOZ_STYLO', delayed_getattr(stylo, 'enabled'))
 
 set_config('MOZ_LIBCLANG_PATH', delayed_getattr(stylo, 'libclang_path'))
 set_config('MOZ_CLANG_PATH', delayed_getattr(stylo, 'clang_path'))
 set_config('MOZ_STYLO_BINDGEN', delayed_getattr(stylo, 'bindgen_enabled'))
 
-@depends(stylo, dmd)
-def jemalloc(stylo, dmd):
-    if stylo:
+@depends(stylo, target, dmd)
+def jemalloc(stylo, target, dmd):
+    if stylo and target.kernel in ('Darwin', 'Linux', 'WINNT'):
+        # Avoid a moving performance target if the default allocator
+        # is changed on Tier1 platforms (see bug 1291356).
         return 'moz'
     elif dmd:
         return True
 
 imply_option('--enable-jemalloc', jemalloc,
              reason='--enable-dmd or --enable-stylo')
 
 option('--with-servo', env='SERVO_TARGET_DIR', nargs=1,