** Return the tail of a command: the basename of the putative executable (which
** could be quoted when containing spaces) and the following arguments.
*/
const char *command_tail(const char *z){
  const char *zTail = z;
  char chQuote = 0;
  if( !zTail ) return 0;
  while( z[0] && (!fossil_isspace(z[0]) ||
                  chQuote) ){
    if( z[0]=='"' || z[0]=='\'' ){
      if( chQuote && chQuote==z[0] )
        chQuote = 0;
      else chQuote = z[0];
    }
    if( fossil_isdirsep(z[0]) ) zTail = &z[1];
    z++;
  }
  return zTail;
}