bmx7: fix compilation with GCC 10

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

bmx7/Makefile

@@ -2,7 +2,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=bmx7
 PKG_VERSION:=7.1.1
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=https://codeload.github.com/bmx-routing/bmx7/tar.gz/v$(PKG_VERSION)?

bmx7/patches/010-gcc10.patch

@@ -0,0 +1,11 @@
+--- a/src/bmx.h
++++ b/src/bmx.h
+@@ -290,7 +290,7 @@ enum ADGSN {
+ #define SUCCESS 0
+ #define FAILURE -1
+ 
+-const void* FAILURE_PTR;
++extern const void* FAILURE_PTR;
+ 
+ 
+ #define MAX_SELECT_TIMEOUT_MS 1100 /* MUST be smaller than (1000/2) to fit into max tv_usec */