thttpd initializes contentlength to -1, so we need to transfer that to 0

for SAPI/PHP.  Otherwise, SAPI will try to read (unsigned long) -1 bytes
from the connection.

sapi/thttpd/thttpd.c

@@ -449,7 +449,8 @@ static void thttpd_request_ctor(TSRMLS_D)
 	SG(request_info).request_method = httpd_method_str(TG(hc)->method);
 	SG(sapi_headers).http_response_code = 200;
 	SG(request_info).content_type = TG(hc)->contenttype;
-	SG(request_info).content_length = TG(hc)->contentlength;
+	SG(request_info).content_length = TG(hc)->contentlength == -1 ? 0
+		: TG(hc)->contentlength;
 	
 	php_handle_auth_data(TG(hc)->authorization TSRMLS_CC);
 }