devel/boehm-gc: Fix functionality on DragonFly

Boehm-gc built on DragonFly, but it wasn't working properly.  This is
one of the major reasons lang/guile20 doesn't build.  Ths fix is proven
as it has been taken from DPorts.

devel/boehm-gc/Makefile

@@ -1,8 +1,8 @@
-# $NetBSD: Makefile,v 1.84 2016/09/28 08:15:30 jperkin Exp $
+# $NetBSD: Makefile,v 1.85 2016/12/03 03:09:26 marino Exp $
 
 DISTNAME=	gc-7.6.0
 PKGNAME=	${DISTNAME:S/gc/boehm-gc/}
-PKGREVISION=	1
+PKGREVISION=	2
 CATEGORIES=	devel
 MASTER_SITES=	http://www.hboehm.info/gc/gc_source/
 

devel/boehm-gc/distinfo

@@ -1,8 +1,11 @@
-$NetBSD: distinfo,v 1.56 2016/09/21 17:59:10 maya Exp $
+$NetBSD: distinfo,v 1.57 2016/12/03 03:09:26 marino Exp $
 
 SHA1 (gc-7.6.0.tar.gz) = bae6b3754ff8d3845b5171346bf924e13be6c693
 RMD160 (gc-7.6.0.tar.gz) = f69b900fed7ae844d355cfccad90cd25214da98e
 SHA512 (gc-7.6.0.tar.gz) = 511e8c01287b1ee9dbec87f0573377de77038b7af053a3f33afed9b3ffa30e2402d6a9bb0ca4f4b81cd808209b47b5718d498cff3de6632a057fe03fad51fc43
 Size (gc-7.6.0.tar.gz) = 1111751 bytes
+SHA1 (patch-configure) = f3bb73ee9535fa2d313bab5d4afa961457c8762c
+SHA1 (patch-dyn__load.c) = 5869f863853a80bb290c8224c4f861a92553e278
 SHA1 (patch-include_private_gc__priv.h) = d9fc570f2ef9d57afe92e63db1f9c5f48b1c0514
 SHA1 (patch-include_private_gcconfig.h) = 23621c34483899df0b3d3dd9f982a1d601c716a0
+SHA1 (patch-tools_threadlibs.c) = 5dd3e8bdbba8806cafcbaa5aa5c0a0778243c8ab

devel/boehm-gc/patches/patch-configure

@@ -0,0 +1,15 @@
+$NetBSD: patch-configure,v 1.1 2016/12/03 03:09:26 marino Exp $
+
+Support DragonFly.
+
+--- configure.orig	2016-08-02 20:23:32 UTC
++++ configure
+@@ -16416,7 +16416,7 @@ $as_echo "$as_me: WARNING: \"Only HP-UX
+         THREADDLLIBS=-pthread
+         AM_CFLAGS="$AM_CFLAGS -pthread"
+         ;;
+-     *-*-freebsd*)
++     *-*-freebsd*|*-*-dragonfly*)
+         { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: \"FreeBSD does not yet fully support threads with Boehm GC.\"" >&5
+ $as_echo "$as_me: WARNING: \"FreeBSD does not yet fully support threads with Boehm GC.\"" >&2;}
+         $as_echo "#define GC_FREEBSD_THREADS 1" >>confdefs.h

devel/boehm-gc/patches/patch-dyn__load.c

@@ -0,0 +1,15 @@
+$NetBSD: patch-dyn__load.c,v 1.3 2016/12/03 03:09:26 marino Exp $
+
+Support DragonFly.
+
+--- dyn_load.c.orig	2016-08-02 19:36:14 UTC
++++ dyn_load.c
+@@ -435,7 +435,7 @@ GC_INNER GC_bool GC_register_main_static
+ # pragma weak dl_iterate_phdr
+ #endif
+ 
+-#if (defined(FREEBSD) && __FreeBSD__ >= 7)
++#if (defined(FREEBSD) && __FreeBSD__ >= 7) || defined __DragonFly__
+   /* On the FreeBSD system, any target system at major version 7 shall   */
+   /* have dl_iterate_phdr; therefore, we need not make it weak as above. */
+ # define HAVE_DL_ITERATE_PHDR

devel/boehm-gc/patches/patch-tools_threadlibs.c

@@ -0,0 +1,15 @@
+$NetBSD: patch-tools_threadlibs.c,v 1.1 2016/12/03 03:09:26 marino Exp $
+
+Support DragonFly.
+
+--- tools/threadlibs.c.orig	2016-08-02 19:36:14 UTC
++++ tools/threadlibs.c
+@@ -42,7 +42,7 @@ int main(void)
+ #       ifdef GC_USE_DLOPEN_WRAP
+           printf("-ldl ");
+ #       endif
+-#       if (__FREEBSD_version >= 500000)
++#       if (__FREEBSD_version >= 500000) || defined __DragonFly__
+           printf("-lpthread\n");
+ #       else
+           printf("-pthread\n");