There is an issue with custom icons on directories in the 2.5c2 installer,
don't set a custom icon on "/Applications/MacPython 2.5" for now.
Also make sure that the installer doesn't crap out when the Makefile in the
system's python installation has other customizations than we expect.
way the resulting binaries have a better change of running on 10.3.
This patch also updates the search logic for sleepycat db3/4, without this
patch you cannot use a sleepycat build with a non-standard prefix; with this
you can (at least on OSX) if you add the prefix to CPPFLAGS/LDFLAGS at
configure-time. This change is needed to build the binary installer for OSX.