Fix an incorrect pointer usage and pass the right pointer to freeifaddrs(),

which would cause a free() inside allocated chunk.

Without this change, the class could crash with jemalloc debugging options
enabled.  The patch have also been submitted to upstream maintainer.

Reported by:	lev
Submitted by:	delphij
PR:		ports/167938
Approved by:	perl@ (swills)

net/p5-IO-Interface/Makefile

@@ -7,6 +7,7 @@
 
 PORTNAME=	IO-Interface
 PORTVERSION=	1.06
+PORTREVISION=	1
 CATEGORIES=	net perl5
 MASTER_SITES=	CPAN
 PKGNAMEPREFIX=	p5-

net/p5-IO-Interface/files/patch-Interface.xs

@@ -0,0 +1,27 @@
+--- ./Interface.xs.orig	2008-06-06 08:51:42.000000000 -0700
++++ ./Interface.xs	2012-05-15 13:16:22.856348098 -0700
+@@ -567,6 +567,7 @@
+      struct ifreq   ifr;
+ #if (defined(USE_GETIFADDRS) && defined(HAVE_SOCKADDR_DL_STRUCT))
+      struct ifaddrs* ifap = NULL;
++     struct ifaddrs* saved_ifap = NULL;
+      struct sockaddr_dl* sdl;
+      sa_family_t  family;
+      char *sdlname, *haddr, *s;
+@@ -581,6 +582,7 @@
+ #endif
+ #if (defined(USE_GETIFADDRS) && defined(HAVE_SOCKADDR_DL_STRUCT))
+      getifaddrs(&ifap);
++     saved_ifap = ifap;
+ 
+      while(1) {
+        if (ifap == NULL) break;
+@@ -595,7 +597,7 @@
+        }
+        ifap = ifap -> ifa_next;
+      } 
+-     freeifaddrs(ifap);
++     freeifaddrs(saved_ifap);
+ 
+      s = hwaddr; 
+      s[0] = '\0';