Description: relax hostname restrictions
Origin: stolen from Debian Jessie update. Thanks!

--- apache2.orig/server/vhost.c
+++ apache2/server/vhost.c
@@ -758,7 +758,7 @@ static apr_status_t strict_hostname_chec
         if (!apr_isascii(*ch)) {
             goto bad;
         }
-        else if (apr_isalpha(*ch) || *ch == '-') {
+        else if (apr_isalpha(*ch) || *ch == '-' || *ch == '_') {
             is_dotted_decimal = 0;
         }
         else if (ch[0] == '.') {
