Fix build under Solaris (10 i86pc with GCC 4.5).

net/iftop/distinfo

@@ -1,6 +1,7 @@
-$NetBSD: distinfo,v 1.4 2009/07/07 21:20:37 joerg Exp $
+$NetBSD: distinfo,v 1.5 2013/03/30 22:28:55 tron Exp $
 
 SHA1 (iftop-0.17.tar.gz) = 75ce6afc8c0bf851278b0a15e66f523af90cfda9
 RMD160 (iftop-0.17.tar.gz) = 0111fdd3d2ba068acd41d9279c987d6699840736
 Size (iftop-0.17.tar.gz) = 160381 bytes
 SHA1 (patch-aa) = 1c0c12967ba01d18f2826f874a8f5a076d88c31b
+SHA1 (patch-dlcommon.h) = 787296f9d337a6b6a5ef080452cd14a3580a5fc3

net/iftop/patches/patch-dlcommon.h

@@ -0,0 +1,13 @@
+$NetBSD: patch-dlcommon.h,v 1.1 2013/03/30 22:28:55 tron Exp $
+
+Fix build problem under Solaris.
+
+--- dlcommon.h.orig	Sat Jun  7 00:42:34 2003
++++ dlcommon.h	Sat Mar 30 23:23:44 2013
+@@ -32,6 +32,5 @@
+ /*
+  * externs go here
+  */
+-extern	void	sigalrm();
+ 
+ #endif /* !DLCOMMON_H */