Without testing it, I'd guess the patch wouldn't hurt but it also wouldn't affect the OS X installer build as the installer script builds a local copy of Sleepycat db4 (since none is included in OS X) and supplies it as an additional local library/include file which is always found first by the setup.py code, so it never gets to searching the additional paths affected by the patch.  If you are building manually and don't supply a local lib, then the build of the dbm extension will either fail or it will try to use a MacPorts or Fink version if available.