Warn rather than dying horribly when mime_content_type function is unavailable

Signed-off-by: Richard Mansfield <richardm@catalyst.net.nz>

htdocs/lang/en.utf8/error.php

@@ -43,6 +43,7 @@ $string['registerglobals'] = 'You have dangerous PHP settings, register_globals
 $string['magicquotesgpc'] = 'You have dangerous PHP settings, magic_quotes_gpc is on. Mahara is trying to work around this, but you should really fix it';
 $string['magicquotesruntime'] = 'You have dangerous PHP settings, magic_quotes_runtime is on. Mahara is trying to work around this, but you should really fix it';
 $string['magicquotessybase'] = 'You have dangerous PHP settings, magic_quotes_sybase is on. Mahara is trying to work around this, but you should really fix it';
+$string['mimemagicnotloaded'] = 'Your server does not have the mime_magic extension enabled. Mahara may have trouble detecting file types.';
 
 $string['safemodeon'] = 'Your server appears to be running safe mode. Mahara does not support running in safe mode. You must turn this off in either the php.ini file, or in your apache config for the site.
 

htdocs/lib/mahara.php

@@ -76,6 +76,12 @@ function ensure_sanity() {
     if (!extension_loaded('dom')) {
         throw new ConfigSanityException(get_string('domextensionnotloaded', 'error'));
     }
+    if (!function_exists('mime_content_type')) {
+        log_environ(get_string('mimemagicnotloaded', 'error'));
+        function mime_content_type($filename) {
+            return 'application/octet-stream';
+        }
+    }
 
     //Check for freetype in the gd extension
     $gd_info = gd_info();