Can nginx automaticly add Content-Type header when there is no
Content-Type header in backend response with X-Accel-Redirect?
I am taking use of X-Accel-Redirect to do the privacy control for
static files. And I have to add the Content-Type header by the backend
CGI programs. If nginx could do so, the backend CGI programs using
X-Accel-Redirect will feel much better and more efficient.