In a threads-disabled build, typing Ctrl-C into a raw_input() crashed,

because (essentially) I didn't realise that PY_BEGIN/END_ALLOW_THREADS
actually expanded to nothing under a no-threads build, so if you somehow
NULLed out the threadstate (e.g. by calling PyThread_SaveThread) it would
stay NULLed when you return to Python.  Argh!

Backport candidate.

Misc/NEWS

@@ -12,6 +12,9 @@ What's New in Python 2.5 alpha 1?
 Core and builtins
 -----------------
 
+- Typing Ctrl-C whilst raw_input() was waiting in a build with threads
+  disabled caused a crash.
+
 - Bug #1165306: instancemethod_new allowed the creation of a method
   with im_class == im_self == NULL, which caused a crash when called.
 

Modules/readline.c

@@ -775,9 +775,13 @@ readline_until_enter_or_signal(char *prompt, int *signal)
 		}
 		else if (errno == EINTR) {
 			int s;
+#ifdef WITH_THREAD
 			PyEval_RestoreThread(_PyOS_ReadlineTState);
+#endif
 			s = PyErr_CheckSignals();
+#ifdef WITH_THREAD
 			PyEval_SaveThread();	
+#endif
 			if (s < 0) {
 				rl_free_line_state();
 				rl_cleanup_after_signal();

Parser/myreadline.c

@@ -82,9 +82,13 @@ my_fgets(char *buf, int len, FILE *fp)
 #ifdef EINTR
 		if (errno == EINTR) {
 			int s;
+#ifdef WITH_THREAD
 			PyEval_RestoreThread(_PyOS_ReadlineTState);
+#endif
 			s = PyErr_CheckSignals();
+#ifdef WITH_THREAD
 			PyEval_SaveThread();
+#endif
 			if (s < 0) {
 				return 1;
 			}