d_vfork should be "$define", even if it produces a bogus "WHOA THERE"

warning; setting it to "true" doesn't work.

lang/perl5/patches/patch-af

@@ -1,7 +1,7 @@
-$NetBSD: patch-af,v 1.4 1998/12/02 02:28:30 tv Exp $
+$NetBSD: patch-af,v 1.5 1998/12/02 15:41:02 tv Exp $
 
 --- hints/netbsd.sh.orig	Thu May  8 11:52:59 1997
-+++ hints/netbsd.sh	Tue Dec  1 20:41:28 1998
++++ hints/netbsd.sh	Wed Dec  2 10:38:28 1998
 @@ -1,12 +1,11 @@
  # hints/netbsd.sh
  #
@@ -74,7 +74,7 @@ $NetBSD: patch-af,v 1.4 1998/12/02 02:28:30 tv Exp $
 +esac
 +
 +# there's no problem with vfork.
-+d_vfork=true
++d_vfork="$define"
 +
 +# in case the user installs a shared libperl, with or without the static lib,
 +# give us a "rpath" for third party binary builds: