Description:
------------
If a string you write to a CSV file with fputcsv() ends with an _odd_ number of backslashes, then when you read it back in with fgetcsv(), it'll miss the delimeter and combine two elements into one.

Reproduce code:
---------------
$tmp_file = '/tmp/csv_f_up.tmp';

$data_to_write = array('string ends with _odd_ number of backslashes \\\\\\',"and isn't the last element");

echo "data_to_write:\n";
var_dump($data_to_write);

$h_w = fopen($tmp_file, 'w');
fputcsv($h_w, $data_to_write);
fclose($h_w);

$h_r = fopen($tmp_file, 'r');
$data_read_in = fgetcsv($h_r);
fclose($h_r);

echo "data_read_in:\n";
var_dump($data_read_in);

Expected result:
----------------
data_to_write:
array(2) {
  [0]=>
  string(48) "string ends with _odd_ number of backslashes \\\"
  [1]=>
  string(26) "and isn't the last element"
}
data_read_in:
array(2) {
  [0]=>
  string(48) "string ends with _odd_ number of backslashes \\\"
  [1]=>
  string(26) "and isn't the last element"
}
}

Actual result:
--------------
data_to_write:
array(2) {
  [0]=>
  string(48) "string ends with _odd_ number of backslashes \\\"
  [1]=>
  string(26) "and isn't the last element"
}
data_read_in:
array(1) {
  [0]=>
  string(77) "string ends with _odd_ number of backslashes \\\",and isn't the last element""
}