http://bugs.gentoo.org/122698
https://gcc.gnu.org/ml/gcc-patches/2015-05/msg02854.html

--- gcc/config/netbsd-elf.h
+++ gcc/config/netbsd-elf.h
@@ -83,6 +83,7 @@
 #define NETBSD_LINK_SPEC_ELF \
   "%{assert*} %{R*} %{rpath*} \
    %{shared:-shared} \
+   %{symbolic:-Bsymbolic} \
    %{!shared: \
      -dc -dp \
      %{!nostdlib: \