fctix-engines.mozc: fix build

This fixes:

FAILED: obj/engine/engine.engine.o
clang++ -MMD -MF obj/engine/engine.engine.o.d -DOS_LINUX -DMOZC_BUILD -DCHANNEL_DEV -DENABLE_GTK_RENDERER -DNDEBUG -DQT_NO_DEBUG -DNO_LOGGING -DIGNORE_HELP_FLAG -DIGNORE_INVALID_FLAG -I/build/source/src -Igen -Igen/proto_out -Wall -Wno-char-subscripts -Wno-sign-compare -Wno-deprecated-declarations -Wwrite-strings -fPIC -fno-exceptions -fmessage-length=0 -fno-strict-aliasing -funsigned-char -include base/namespace.h -pipe -pthread -fno-omit-frame-pointer -fstack-protector --param=ssp-buffer-size=4 -Wtype-limits -O2 -Wno-deprecated -Wno-covered-switch-default -Wno-unnamed-type-template-args -Wno-c++11-narrowing -std=gnu++0x -std=gnu++0x  -c ../../engine/engine.cc -o obj/engine/engine.engine.o
In file included from ../../engine/engine.cc:30:
In file included from /build/source/src/engine/engine.h:33:
In file included from /nix/store/pcs8pq4a5rkym1hzibqz7da45fxkmig7-gcc-8.3.0/include/c++/8.3.0/memory:62:
In file included from /nix/store/pcs8pq4a5rkym1hzibqz7da45fxkmig7-gcc-8.3.0/include/c++/8.3.0/bits/stl_algobase.h:66:
/nix/store/pcs8pq4a5rkym1hzibqz7da45fxkmig7-gcc-8.3.0/include/c++/8.3.0/bits/stl_iterator_base_funcs.h:183:2: error: cannot decrement value of type 'mozc::ZeroQueryDict::iterator'
        --__i;
        ^ ~~~
/nix/store/pcs8pq4a5rkym1hzibqz7da45fxkmig7-gcc-8.3.0/include/c++/8.3.0/bits/stl_iterator_base_funcs.h:206:12: note: in instantiation of function template specialization 'std::__advance<mozc::ZeroQueryDict::iterator, long>' requested here
      std::__advance(__i, __d, std::__iterator_category(__i));
           ^
/nix/store/pcs8pq4a5rkym1hzibqz7da45fxkmig7-gcc-8.3.0/include/c++/8.3.0/bits/stl_algo.h:2137:9: note: in instantiation of function template specialization 'std::advance<mozc::ZeroQueryDict::iterator, long>' requested here
          std::advance(__middle, __half);
               ^
/nix/store/pcs8pq4a5rkym1hzibqz7da45fxkmig7-gcc-8.3.0/include/c++/8.3.0/bits/stl_algo.h:2190:19: note: in instantiation of function template specialization 'std::__equal_range<mozc::ZeroQueryDict::iterator, unsigned long, __gnu_cxx::__ops::_Iter_less_val, __gnu_cxx::__ops::_Val_less_iter>' requested here
      return std::__equal_range(__first, __last, __val,
                  ^
/build/source/src/prediction/zero_query_dict.h:213:17: note: in instantiation of function template specialization 'std::equal_range<mozc::ZeroQueryDict::iterator, unsigned long>' requested here
    return std::equal_range(begin(), end(), iter.index());
                ^
1 error generated.

1 files changed, 5 insertions, 0 deletions

diff --git a/pkgs/tools/inputmethods/fcitx-engines/fcitx-mozc/default.nix b/pkgs/tools/inputmethods/fcitx-engines/fcitx-mozc/default.nix
index d74c7608bc90..9f062036438f 100644
--- a/pkgs/tools/inputmethods/fcitx-engines/fcitx-mozc/default.nix
+++ b/pkgs/tools/inputmethods/fcitx-engines/fcitx-mozc/default.nix
@@ -39,6 +39,11 @@ in clangStdenv.mkDerivation rec {
       url    = "https://download.fcitx-im.org/fcitx-mozc/${name}";
       sha256 = "1f9m4310kz09v5qvnv75ka2vq63m7by023qrkpddgq4dv7gxx3ca";
      })
+    # https://github.com/google/mozc/pull/444 - fix for gcc8 STL
+    (fetchpatch {
+      url = "https://github.com/google/mozc/commit/82d38f929882a9c62289b179c6fe41efed249987.patch";
+      sha256 = "07cja1b7qfsd3i76nscf1zwiav74h7d6h2g9g2w4bs3h1mc9jwla";
+    })
   ];
 
   postPatch = ''