Change framework search order when looking for Tcl/Tk on OSX.

This is needed because the system linker looks in /Library/Framework before
it looks in /System/Library frameworks. Without this patch _tkinter will
be unusable when it is compiled on a system that has Tk 8.5 installed in
/Library/Frameworks (and the Apple 8.4 install in /System/Library/Frameworks)

setup.py

@@ -1443,8 +1443,8 @@ class PyBuildExt(build_ext):
         # different the UNIX search logic is not sharable.
         from os.path import join, exists
         framework_dirs = [
-            '/System/Library/Frameworks/',
             '/Library/Frameworks',
+            '/System/Library/Frameworks/',
             join(os.getenv('HOME'), '/Library/Frameworks')
         ]