"#if WITH_THREAD" is incorrect; must be #ifdef instead; WITH_THREAD
isn't always set to an integer value when it's defined.
diff --git a/Parser/myreadline.c b/Parser/myreadline.c
index ff9fc91..979e34f 100644
--- a/Parser/myreadline.c
+++ b/Parser/myreadline.c
@@ -22,7 +22,7 @@
 
 PyThreadState* _PyOS_ReadlineTState;
 
-#if WITH_THREAD
+#ifdef WITH_THREAD
 #include "pythread.h"
 static PyThread_type_lock _PyOS_ReadlineLock = NULL;
 #endif
@@ -181,7 +181,7 @@
 #endif
 	}
 	
-#if WITH_THREAD
+#ifdef WITH_THREAD
 	if (_PyOS_ReadlineLock == NULL) {
 		_PyOS_ReadlineLock = PyThread_allocate_lock();		
 	}
@@ -189,7 +189,7 @@
 
 	_PyOS_ReadlineTState = PyThreadState_GET();
 	Py_BEGIN_ALLOW_THREADS
-#if WITH_THREAD
+#ifdef WITH_THREAD
 	PyThread_acquire_lock(_PyOS_ReadlineLock, 1);
 #endif
 
@@ -205,7 +205,7 @@
                                                      prompt);
 	Py_END_ALLOW_THREADS
 
-#if WITH_THREAD
+#ifdef WITH_THREAD
 	PyThread_release_lock(_PyOS_ReadlineLock);
 #endif