~ chicken-core (chicken-5) 0667581c7f004fd7395254a7bdf9d2fe58aef403

commit 0667581c7f004fd7395254a7bdf9d2fe58aef403
Author:     felix <felix@call-with-current-continuation.org>
AuthorDate: Tue Jul 27 00:35:47 2010 +0200
Commit:     felix <felix@call-with-current-continuation.org>
CommitDate: Tue Jul 27 00:35:47 2010 +0200

    mutex-unlock! fix in srfi-18

diff --git a/srfi-18.scm b/srfi-18.scm
index 75d98890..9566696b 100644
--- a/srfi-18.scm
+++ b/srfi-18.scm
@@ -372,7 +372,8 @@ EOF
 	   (##sys#setislot mutex 4 #f)
 	   (##sys#setislot mutex 5 #f)
 	   (let ((t (##sys#slot mutex 2)))
-	     (##sys#setslot t 8 (##sys#delq mutex (##sys#slot t 8))))
+	     (when t
+	       (##sys#setslot t 8 (##sys#delq mutex (##sys#slot t 8)))))
 	   (when cvar
 	     (##sys#setslot cvar 2 (##sys#append (##sys#slot cvar 2) (##sys#list ct)))
 	     (##sys#setslot ct 11 cvar)