bfdd: fix compilation with GCC 10

Signed-off-by: Rosen Penev <rosenp@gmail.com>

net/bfdd/Makefile

@@ -8,7 +8,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=bfdd
 PKG_SOURCE_DATE:=2019-08-22
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 
 PKG_SOURCE_VERSION:=c54534beb524afc3972039f57b56ec65332b43f7
 PKG_SOURCE_URL:=https://codeload.github.com/rzalamena/bfdd/tar.gz/$(PKG_SOURCE_VERSION)?

net/bfdd/patches/020-gcc10.patch

@@ -0,0 +1,18 @@
+--- a/bfd.h
++++ b/bfd.h
+@@ -299,13 +299,13 @@ typedef struct bfd_state_str_list_s {
+ 	int type;
+ } bfd_state_str_list;
+ 
+-struct bfd_vrf {
++extern struct bfd_vrf {
+ 	int vrf_id;
+ 	char name[MAXNAMELEN + 1];
+ 	UT_hash_handle vh;
+ } bfd_vrf;
+ 
+-struct bfd_iface {
++extern struct bfd_iface {
+ 	int vrf_id;
+ 	char ifname[MAXNAMELEN + 1];
+ 	UT_hash_handle ifh;