t4kcommon: add -fcommon workaround

Workaround build failure on -fno-common toolchains like upstream
gcc-10. Otherwise build fails as:

    ld: CMakeFiles/t4k_common.dir/t4k_throttle.c.o:(.bss+0x0): multiple definition of
      `wrapped_lines'; CMakeFiles/t4k_common.dir/t4k_audio.c.o:(.bss+0x0): first defined here

1 files changed, 7 insertions, 0 deletions

diff --git a/pkgs/games/t4kcommon/default.nix b/pkgs/games/t4kcommon/default.nix
index 74757c236c51b..4a7a2e92b106a 100644
--- a/pkgs/games/t4kcommon/default.nix
+++ b/pkgs/games/t4kcommon/default.nix
@@ -19,6 +19,13 @@ stdenv.mkDerivation rec {
     })
   ];
 
+  # Workaround build failure on -fno-common toolchains like upstream
+  # gcc-10. Otherwise build fails as:
+  #   ld: CMakeFiles/t4k_common.dir/t4k_throttle.c.o:(.bss+0x0): multiple definition of
+  #     `wrapped_lines'; CMakeFiles/t4k_common.dir/t4k_audio.c.o:(.bss+0x0): first defined here
+  # TODO: revisit https://github.com/tux4kids/t4kcommon/pull/10 when merged.
+  NIX_CFLAGS_COMPILE = "-fcommon";
+
   nativeBuildInputs = [ cmake pkg-config ];
   buildInputs = [ SDL SDL_image SDL_mixer SDL_net SDL_ttf libpng librsvg libxml2 ];