Use intra-DSO calls when we build libbusybox. No-op for normal build.
This was Bernhard Fischer' idea.

   text    data     bss     dec     hex filename
 773549    7781    9740  791070   c121e busybox.t7/0_lib/libbusybox.so.1.11.0.svn_unstripped
 769683    7397    9740  786820   c0184 busybox.t9t/0_lib/libbusybox.so.1.11.0.svn_unstripped

diff --git a/networking/libiproute/ll_map.h b/networking/libiproute/ll_map.h
index 55e2cf3..c425789 100644
--- a/networking/libiproute/ll_map.h
+++ b/networking/libiproute/ll_map.h
@@ -2,6 +2,10 @@
 #ifndef __LL_MAP_H__
 #define __LL_MAP_H__ 1
 
+#if __GNUC_PREREQ(4,1)
+# pragma GCC visibility push(hidden)
+#endif
+
 int ll_remember_index(struct sockaddr_nl *who, struct nlmsghdr *n, void *arg);
 int ll_init_map(struct rtnl_handle *rth);
 int xll_name_to_index(const char *const name);
@@ -10,4 +14,8 @@
 /* int ll_index_to_type(int idx); */
 unsigned ll_index_to_flags(int idx);
 
+#if __GNUC_PREREQ(4,1)
+# pragma GCC visibility pop
+#endif
+
 #endif /* __LL_MAP_H__ */