Patch by Fred Gansevles.

This patch solves 2 problems of the os module.
1) Bug ID #50 (case-mismatch wiht "environ.get(..,..)" and "del environ[..]")
2) os.environ.update (dict) doesn't propagate changes to the 'real'
   environment (i.e doesn't call putenv)

This patches also has minor changes specific for 1.6a
The string module isn't used anymore, instead the strings own methods are
used.

Lib/os.py

@@ -220,8 +220,7 @@ def _execvpe(file, args, env=None):
         envpath = env['PATH']
     else:
         envpath = defpath
-    import string
-    PATH = string.splitfields(envpath, pathsep)
+    PATH = envpath.split(pathsep)
     if not _notfound:
         import tempfile
         # Exec a file that is guaranteed not to exist
@@ -248,22 +247,26 @@ else:
 
     if name in ('os2', 'nt', 'dos'):  # Where Env Var Names Must Be UPPERCASE
         # But we store them as upper case
-        import string
         class _Environ(UserDict.UserDict):
             def __init__(self, environ):
                 UserDict.UserDict.__init__(self)
                 data = self.data
-                upper = string.upper
                 for k, v in environ.items():
-                    data[upper(k)] = v
+                    data[k.upper()] = v
             def __setitem__(self, key, item):
                 putenv(key, item)
-                key = string.upper(key)
-                self.data[key] = item
+                self.data[key.upper()] = item
             def __getitem__(self, key):
-                return self.data[string.upper(key)]
+                return self.data[key.upper()]
+            def __delitem__(self, key):
+                del self.data[key.upper()]
             def has_key(self, key):
-                return self.data.has_key(string.upper(key))
+                return self.data.has_key(key.upper())
+            def get(self, key, failobj=None):
+                return self.data.get(key.upper(), failobj)
+            def update(self, dict):
+                for k, v in dict.items():
+                    self[k] = v
 
     else:  # Where Env Var Names Can Be Mixed Case
         class _Environ(UserDict.UserDict):
@@ -273,6 +276,9 @@ else:
             def __setitem__(self, key, item):
                 putenv(key, item)
                 self.data[key] = item
+            def update(self, dict):
+                for k, v in dict.items():
+                    self[k] = v
 
     environ = _Environ(environ)