Relax the rules for using 'from ... import *' and exec in the presence
of nested functions.  Either is allowed in a function if it contains
no defs or lambdas or the defs and lambdas it contains have no free
variables.  If a function is itself nested and has free variables,
either is illegal.

Revise the symtable to use a PySymtableEntryObject, which holds all
the revelent information for a scope, rather than using a bunch of
st_cur_XXX pointers in the symtable struct.  The changes simplify the
internal management of the current symtable scope and of the stack.

Added new C source file: Python/symtable.c.  (Does the Windows build
process need to be updated?)

As part of these changes, the initial _symtable module interface
introduced in 2.1a2 is replaced.  A dictionary of
PySymtableEntryObjects are returned.
diff --git a/Makefile.pre.in b/Makefile.pre.in
index 43d1dad..f6dabe6 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -228,6 +228,7 @@
 		Python/pystate.o \
 		Python/pythonrun.o \
 		Python/structmember.o \
+		Python/symtable.o \
 		Python/sysmodule.o \
 		Python/traceback.o \
 		Python/getopt.o \