--- src/xcb_conn.c.orig	2007-03-03 17:05:12.000000000 +0100
+++ src/xcb_conn.c	2007-03-03 17:18:25.000000000 +0100
@@ -62,6 +62,11 @@
 static int _xcb_xlib_init(_xcb_xlib *xlib)
 {
     xlib->lock = 0;
+    xlib->sloppy_lock = 0;
+
+    if (getenv("LIBXCB_ALLOW_SLOPPY_LOCK"))
+        xlib->sloppy_lock = 1;
+
     pthread_cond_init(&xlib->cond, 0);
     return 1;
 }
--- src/xcbint.h.orig	2007-03-03 17:05:00.000000000 +0100
+++ src/xcbint.h	2007-03-03 17:10:33.000000000 +0100
@@ -130,6 +130,7 @@
 
 typedef struct _xcb_xlib {
     int lock;
+    int sloppy_lock;
     pthread_t thread;
     pthread_cond_t cond;
 } _xcb_xlib;
--- src/xcb_xlib.c.orig	2007-03-03 17:07:06.000000000 +0100
+++ src/xcb_xlib.c	2007-03-03 17:10:14.000000000 +0100
@@ -40,7 +40,8 @@
 void xcb_xlib_lock(xcb_connection_t *c)
 {
     _xcb_lock_io(c);
-    assert(!c->xlib.lock);
+    if (!c->xlib.sloppy_lock)
+	    assert(!c->xlib.lock);
     c->xlib.lock = 1;
     c->xlib.thread = pthread_self();
     _xcb_unlock_io(c);
@@ -49,7 +50,8 @@
 void xcb_xlib_unlock(xcb_connection_t *c)
 {
     _xcb_lock_io(c);
-    assert(c->xlib.lock);
+    if (!c->xlib.sloppy_lock)
+	assert(c->xlib.lock);
     assert(pthread_equal(c->xlib.thread, pthread_self()));
     c->xlib.lock = 0;
     pthread_cond_broadcast(&c->xlib.cond);