My current quick-and-very-dirty workaround looks like this:
froxlor/scripts/jobs/cron_tasks.inc.http.30.nginx.php
if ($domain['phpenabled_customer'] == 1 && $domain['phpenabled_vhost'] == '1') {
$webroot_text .= "\t" . 'index index.php index.html index.htm;' . "\n";
if (!preg_match("/^##NO_TRY_FILES$/m", $domain['specialsettings']))
{
$webroot_text .= "\t\t" . 'try_files $uri $uri/ @rewrites;' . "\n";
} else {
// NO_TRY_FILES statement found, don't put try_files into config
}
} else {
$webroot_text .= "\t" . 'index index.html index.htm;' . "\n";
}
If I now put the statement "##NO_TRY_FILES" on a line by itself into the vhost special settings, no "try_files" will be generated in "location /".