message: FileUtil::exists for linux
diff: #include "fileutil.h"
  #include <Tempest/Platform>
  +#include <Tempest/TextCodec>
  +
  #ifdef __WINDOWS__
  #include <windows.h>
  #include <shlwapi.h>
  @@ -12,8 +14,8 @@ bool FileUtil::exists(const std::u16string &path) {
  #ifdef __WINDOWS__
  return PathFileExistsW(reinterpret_cast<const WCHAR*>(path.c_str()));
  #else
  + std::string p=Tempest::TextCodec::toUtf8(path);
  struct stat buffer={};
  - return stat("path to utf8",&buffer);
  - return false;
  + return stat(p.c_str(),&buffer)==0;
  #endif
  }
  