Description:
------------
Seems to be a common problem nobody complains about...
"is_executable()" does not work in safe_mode!

Some PHP-Projects check for sendmail using this function and don't work in safe_mode even if sendmail acutally IS executable (i.e. PEAR: Mail.php).

is_executable() should at least honor the safe_mode_exec_dir directive!

Reproduce code:
---------------
<?php
if( is_executable( "/usr/sbin/sendmail" ) ) {
   print ("no probs!\n");
}
else {
   print ("this really sucks!\n");
}
?>

Try with PHP/CGI and suexec + safe_mode
where example-UID != sendmail-UID


Expected result:
----------------
true, what else?

Actual result:
--------------
false.