Gecko is missing `libstdc++.so.6` about nixpkgs-mozilla HOT 5 CLOSED

$ nix-locate -w libstdc++.so.6
# ...
(gcc45.out)                                           0 s /nix/store/6v26wdxwsb4zpdv6a2h51ap3xmqc8hxx-gcc-4.5.4/lib/libstdc++.so.6
(gcc6.out)                                            0 s /nix/store/g9vzssx7j2rabwgqwp7zfpx8kfl7jdmn-gcc-6.4.0-lib/lib/libstdc++.so.6
(gccgo.out)                                           0 s /nix/store/lq0nclmp3bmdk1zp193kwnnyz802mld6-gccgo6-6.4.0/lib/libstdc++.so.6
(gcc_debug.out)                                       0 s /nix/store/9bakzmnahi9vpx0snprnvq9gcxbycxga-gcc-debug-6.4.0-lib/lib/libstdc++.so.6
gcc-unwrapped.lib                                     0 s /nix/store/1fw5cgb5fi5aihs8hqqy0jbarbvkan1c-gcc-6.4.0-lib/lib/libstdc++.so.6
# ...

$ mkdir /tmp/gecko
$ cd /tmp/gecko
$ git clone --depth 1 https://github.com/mozilla/nixpkgs-mozilla.git
$ git clone --depth 1 https://github.com/mozilla/gecko-dev.git
$ cd gecko-dev
$ nix-shell ../nixpkgs-mozilla/release.nix -A gecko.x86_64-linux.gcc --run './mach build && ./mach run'

$ ldd ~/mozilla/_build/firefox/bugzil.la/1104647/wip/x64/gcc/dbg/dist/bin/firefox
        linux-vdso.so.1 (0x00007ffdf1d7e000)
        libpthread.so.0 => /nix/store/s7dw1yngwiskqa2ac1bkc6m9g7740agg-glibc-2.25/lib/libpthread.so.0 (0x00007f5e965d9000)
        libdl.so.2 => /nix/store/s7dw1yngwiskqa2ac1bkc6m9g7740agg-glibc-2.25/lib/libdl.so.2 (0x00007f5e963d5000)
        libstdc++.so.6 => /nix/store/vzbrk9ic04h3243rk8ymckb611pkjkkd-gcc-5.4.0-lib/lib/libstdc++.so.6 (0x00007f5e9605d000)
        libm.so.6 => /nix/store/s7dw1yngwiskqa2ac1bkc6m9g7740agg-glibc-2.25/lib/libm.so.6 (0x00007f5e95d4b000)
        libgcc_s.so.1 => /nix/store/s7dw1yngwiskqa2ac1bkc6m9g7740agg-glibc-2.25/lib/libgcc_s.so.1 (0x00007f5e95b35000)
        libc.so.6 => /nix/store/s7dw1yngwiskqa2ac1bkc6m9g7740agg-glibc-2.25/lib/libc.so.6 (0x00007f5e95798000)
        /nix/store/s7dw1yngwiskqa2ac1bkc6m9g7740agg-glibc-2.25/lib/ld-linux-x86-64.so.2 (0x00007f5e967f7000)