Move the signal module back into Setup.config.in so it can be enabled

and disabled from the configure script.

Modules/Setup.config.in

@@ -9,5 +9,8 @@
 # Threading
 @USE_THREAD_MODULE@thread threadmodule.c
 
+# The signal module
+@USE_SIGNAL_MODULE@signal signalmodule.c
+
 # The rest of the modules previously listed in this file are built
 # by the setup.py script in Python 2.1.

Modules/Setup.dist

@@ -97,9 +97,6 @@ PYTHONPATH=$(COREPYTHONPATH)
 posix posixmodule.c		# posix (UNIX) system calls
 _sre _sre.c			# Fredrik Lundh's new regular expressions
 
-# The signal module can't be compiled as a dynamically linked module.
-signal signalmodule.c           # signal(2)
-
 # The rest of the modules listed in this file are all commented out by
 # default.  Usually they can be detected and built as dynamically
 # loaded modules by the new setup.py script added in Python 2.1.  If