lispmob: fix build with musl

lispmob accesses the gnu members of struct udphdr like source and dest
and does not use the posix member names. Instead of using the correct
names just define this as _GNU_SOURCE.

[bump PKG_RELEASE]
Signed-off-by: Etienne CHAMPETIER <champetier.etienne@gmail.com>
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

Signed-off-by: Etienne CHAMPETIER <champetier.etienne@gmail.com>

net/lispmob/Makefile

@@ -10,7 +10,7 @@ include $(TOPDIR)/rules.mk
 PKG_NAME:=lispmob
 PKG_REV:=180aa39d338a00bb532e421de7f8513492cf2e8b
 PKG_VERSION:=0.4
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:=git://github.com/LISPmob/lispmob.git

net/lispmob/patches/001-fix-musl-build.patch

@@ -0,0 +1,31 @@
+--- a/lispd/lispd_output.c
++++ b/lispd/lispd_output.c
+@@ -26,6 +26,7 @@
+  *    Alberto Rodriguez Natal <arnatal@ac.upc.edu>
+  */
+ 
++#define _GNU_SOURCE 1
+ 
+ 
+ #include <assert.h>
+--- a/lispd/lispd_input.c
++++ b/lispd/lispd_input.c
+@@ -26,6 +26,7 @@
+  *    Alberto Rodriguez Natal <arnatal@ac.upc.edu>
+  */
+ 
++#define _GNU_SOURCE 1
+ 
+ #include "lispd_input.h"
+ #include "lispd_map_notify.h"
+--- a/lispd/lispd_pkt_lib.c
++++ b/lispd/lispd_pkt_lib.c
+@@ -28,6 +28,8 @@
+  *
+  */
+ 
++#define _GNU_SOURCE 1
++
+ #include "lispd_afi.h"
+ #include "lispd_pkt_lib.h"
+ #include "lispd_lib.h"