remove --with(out)-signal-module, since the signal module is non-optional

Modules/Setup.config.in

@@ -6,8 +6,5 @@
 # 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 and later.

Modules/Setup.dist

@@ -117,6 +117,7 @@ _operator _operator.c	        # operator.add() and similar goodies
 _collections _collectionsmodule.c # Container types
 itertools itertoolsmodule.c    # Functions creating iterators for efficient looping
 atexit atexitmodule.c      # Register functions to be run at interpreter-shutdown
+_signal signalmodule.c
 _stat _stat.c			# stat.h interface
 time timemodule.c	# -lm # time operations and variables