--- Libc/Libc-262/gen/sigsetops.c
+++ Libc/Libc-583/gen/sigsetops.c
@@ -3,19 +3,20 @@
  *
  * @APPLE_LICENSE_HEADER_START@
  * 
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
  * 
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
  * 
  * @APPLE_LICENSE_HEADER_END@
  */
@@ -62,6 +63,7 @@
 #undef sigdelset
 #undef sigismember
 
+int
 sigemptyset(set)
 	sigset_t *set;
 {
@@ -69,6 +71,7 @@
 	return (0);
 }
 
+int
 sigfillset(set)
 	sigset_t *set;
 {
@@ -76,6 +79,7 @@
 	return (0);
 }
 
+int
 sigaddset(set, signo)
 	sigset_t *set;
 	int signo;
@@ -84,10 +88,13 @@
 		errno = EINVAL;
 		return(-1);
 	}
+	if (signo == 0)
+		return(0);
 	*set |= sigmask(signo);
 	return (0);
 }
 
+int
 sigdelset(set, signo)
 	sigset_t *set;
 	int signo;
@@ -96,10 +103,13 @@
 		errno = EINVAL;
 		return(-1);
 	}
+	if (signo == 0)
+		return(0);
 	*set &= ~sigmask(signo);
 	return (0);
 }
 
+int
 sigismember(set, signo)
 	const sigset_t *set;
 	int signo;
@@ -108,5 +118,7 @@
 		errno = EINVAL;
 		return(-1);
 	}
-	return ((*set & ~sigmask(signo)) != 0);
+	if (signo == 0)
+		return(0);
+	return ((*set & sigmask(signo)) != 0);
 }