sanity: check whether SELF_URL_PATH conforms to data returned by httpd

include/sanity_check.php

@@ -97,11 +97,17 @@
 				}
 			}
 
+			$ref_self_url_path = make_self_url_path();
+            $ref_self_url_path = preg_replace("/\w+\.php$/", "", $ref_self_url_path);
+
 			if (SELF_URL_PATH == "http://example.org/tt-rss/") {
-				$urlpath = preg_replace("/\w+\.php$/", "", make_self_url_path());
+				array_push($errors,
+						"Please set SELF_URL_PATH to the correct value for your server (possible value: <b>$ref_self_url_path</b>)");
+			}
 
+			if (SELF_URL_PATH != $ref_self_url_path && (!defined('_SKIP_SELF_URL_PATH_CHECKS') || !_SKIP_SELF_URL_PATH_CHECKS)) {
                 array_push($errors,
-						"Please set SELF_URL_PATH to the correct value for your server (possible value: <b>$urlpath</b>)");
+                    "Please set SELF_URL_PATH to the correct value detected for your server: <b>$ref_self_url_path</b>");
             }
 
             if (!is_writable(ICONS_DIR)) {