PVS-Studio warning V547 for DeSmuME

int str_ltrim(char *str, int flags) {
  ...
  while (str[0]) {
    if ((str[0] != ' ') || (str[0] != '\t') ||
        (str[0] != '\r') || (str[0] != '\n'))
      break;
  ...
}

This suspicious code was found in DeSmuME project by PVS-Studio static code analyzer.
Warning message is:
V547 Expression '(str[0] != ' ') || (str[0] != '\t')' is always true. Probably the '&&' operator should be used here. DeSmuME_VS2005 xstring.cpp 93

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