Description:
------------
I have the same issue under FreeBSD 10 with php-5.5.14 as #50524 but only with proc_open(). Under Linux I got the expected result.

Test script:
---------------
<?php
chdir('/home/webadmin/test');
$fdSpecs = array(
1 => array('pipe', 'w'),
2 => array('pipe', 'w'),
);
$process = proc_open('php -r "var_dump(getcwd());"', $fdSpecs, $pipes);
echo 'Without $cwd argument:', PHP_EOL;
echo stream_get_contents($pipes[1]);

echo PHP_EOL;

$process = proc_open('php -r "var_dump(getcwd());"', $fdSpecs, $pipes, NULL);
echo 'With NULL as $cwd argument:', PHP_EOL;
echo stream_get_contents($pipes[1]);

echo PHP_EOL;

$process = proc_open('php -r "var_dump(getcwd());"', $fdSpecs, $pipes, getcwd());
echo 'With getcwd() as $cwd argument:', PHP_EOL;
echo stream_get_contents($pipes[1]);

echo PHP_EOL;

$process = proc_open('php -r "var_dump(getcwd());"', $fdSpecs, $pipes, '/');
echo 'With "/" as $cwd argument:', PHP_EOL;
echo stream_get_contents($pipes[1]);

echo PHP_EOL;

echo 'Exec $CWD: ', PHP_EOL;
echo exec('php -r "var_dump(getcwd());"'), PHP_EOL;
?>

Expected result:
----------------
Without $cwd argument:
string(14) "/home/webadmin/test"

With NULL as $cwd argument:
string(14) "/home/webadmin/test"

With getcwd() as $cwd argument:
string(19) "/home/webadmin/test"

With "/" as $cwd argument:
string(1) "/"

Exec $CWD: 
string(19) "/home/webadmin/test"

Actual result:
--------------
Without $cwd argument:
string(14) "/home/webadmin"

With NULL as $cwd argument:
string(14) "/home/webadmin"

With getcwd() as $cwd argument:
string(19) "/home/webadmin/test"

With "/" as $cwd argument:
string(1) "/"

Exec $CWD: 
string(19) "/home/webadmin/test"