If a --python option is used to specify the Python to use in the #!

line also use this as the executable in the bundle.

Lib/plat-mac/bundlebuilder.py

@@ -405,6 +405,9 @@ class AppBuilder(BundleBuilder):
         if self.executable is None:
             if not self.standalone and not isFramework():
                 self.symlink_exec = 1
+            if self.python:
+                self.executable = self.python
+            else:
                 self.executable = sys.executable
 
         if self.nibname: