Avoid duplicate symbol error when linking with lld(1).

Mark the default usage() implementation as weak.

databases/virtuoso/Makefile

@@ -1,10 +1,10 @@
-# $OpenBSD: Makefile,v 1.15 2017/10/23 17:10:38 sthen Exp $
+# $OpenBSD: Makefile,v 1.16 2017/12/26 18:12:30 jca Exp $
 
 BROKEN-macppc =	make: don't know how to make all
 
 COMMENT =	object-relational SQL database
 DISTNAME =	virtuoso-opensource-6.1.6
-REVISION =	7
+REVISION =	8
 PKGNAME =	${DISTNAME:C/-opensource//}
 
 CATEGORIES =	databases

databases/virtuoso/patches/patch-libsrc_util_usage_c

@@ -0,0 +1,18 @@
+$OpenBSD: patch-libsrc_util_usage_c,v 1.1 2017/12/26 18:12:30 jca Exp $
+
+Mark the default usage() implementation as weak to avoid multiple
+definition errors with lld(1).
+
+Index: libsrc/util/usage.c
+--- libsrc/util/usage.c.orig
++++ libsrc/util/usage.c
+@@ -28,8 +28,7 @@
+ 
+ #include "libutil.h"
+ 
+-
+-void
++void __attribute__((weak))
+ usage (void)
+ {
+   default_usage ();