Cause buildtools to raise a DeprecationWarning.

Lib/plat-mac/buildtools.py

@@ -14,6 +14,9 @@ import macresource
 import EasyDialogs
 import shutil
 
+import warnings
+warnings.warn("the buildtools module is deprecated", DeprecationWarning, 2)
+
 
 BuildError = "BuildError"
 

Misc/NEWS

@@ -909,6 +909,8 @@ Windows
 Mac
 ---
 
+- buildtools now raises a DeprecationWarning.
+
 - Removed the macfs module.  It had been deprecated since Python 2.5.  This
   lead to the deprecation of macostools.touched() as it relied solely on macfs
   and was a no-op under OS X.