Description:
------------
I've reproduced this with 5.6.0 and older versions for windows.
It doesn't matter if it's x32 or x64 but only the thread safe version crashes.
It doesn't crash with nginx but with Apache 2.4.

I start php with the following command:
php-cgi.exe -b 127.0.0.1:9000

In Apache I configure my virtual host
<VirtualHost *:80>
    ServerAdmin webmaster@dummy-host.example.com
    DocumentRoot "c:/x/www"
    ServerName localhost
    ProxyPassMatch ^/(.*\.php(/.*)?)$ fcgi://127.0.0.1:9000/C:/x/www/$1
</VirtualHost>

The first loading if a page works, every second request crashes php-cgi.exe

I've also tried it with a new module mod_proxy_handler and I get the same result
    <FilesMatch "\.php$">
        SetHandler proxy:fcgi://localhost:9000/
    </FilesMatch>

Test script:
---------------
<?php
phpinfo()
?>

Expected result:
----------------
php-cgi.exe shouldn't crash.

Actual result:
--------------
php5ts.dll!_estrdup(const char * s) Line 2630	C
php5ts.dll!virtual_getcwd_ex(unsigned __int64 * length, void * * * tsrm_ls) Line 559	C
php5ts.dll!virtual_getcwd(char * buf, unsigned __int64 size, void * * * tsrm_ls) Line 568	C
php5ts.dll!tsrm_realpath(const char * path, char * real_path, void * * * tsrm_ls) Line 1971	C
php-cgi.exe!init_request_info(_fcgi_request * request, void * * * tsrm_ls) Line 1239	C
php-cgi.exe!main(int argc, char * * argv) Line 2138	C
php-cgi.exe!__tmainCRTStartup() Line 536	C