PHP binary there, but PHPStorm won't recognize/use it.

It looks like the php file is there, but PHPStorm refuses to recognize it.
`vagrant@devbox:/vagrant/.idea/vagrant$ ls -l
total 8
-rwxrwxrwx 1 vagrant vagrant   18 Mar 25 16:36 host_ip
-rwxrwxrwx 1 vagrant vagrant 2095 Mar 24 20:26 php`

Here's PHPStorm's reaction when I try to select the php binary:
![phpstormphp](https://f.cloud.github.com/assets/876146/2516120/84811a74-b44a-11e3-981c-08d18676fba9.png)

Mac Host, Linux guest.  Running VirtualBox.

Am I missing something?  Do the host and guest have to be the same operating system?