yetris: fix compilation on aarch64-linux

https://hydra.nixos.org/build/297262484/nixlog/1

char's are not signed by default on aarch64 systems.

Signed-off-by: Ethan Carter Edwards <[e-mail]>

pkgs/by-name/ye/yetris/package.nix

···
     hash = "sha256-k9CXXIaDk1eAtRBEj0VCfE+D1FtmIDX3niubAdrfjqw=";
   };
 
+  postPatch = ''
+    substituteInPlace src/Game/Entities/RotationSystemSRS.cpp \
+      --replace-fail 'char' 'signed char'
+    substituteInPlace src/Game/Entities/PieceDefinitions.cpp \
+      --replace-fail 'char' 'signed char'
+    substituteInPlace src/Game/Entities/PieceDefinitions.hpp \
+      --replace-fail 'char' 'signed char'
+  '';
+
   buildInputs = [
     ncurses
   ];