On upstream inclusion of the assumed_charset patch (past 1.5.14), file_charset
got renamed to attach_charset. We add it back for compatibility.
-Index: mutt/init.h
-===================================================================
---- mutt.orig/init.h 2007-03-12 19:11:53.000000000 +0100
-+++ mutt/init.h 2007-03-12 19:13:56.000000000 +0100
-@@ -248,6 +248,9 @@ struct option_t MuttVars[] = {
- ** Note: "iso-2022-*" must be put at the head of the value as shown above
- ** if included.
+--- a/init.h
++++ b/init.h
+@@ -208,6 +208,9 @@
+ ** Note: for Japanese users, ``iso-2022-*'' must be put at the head
+ ** of the value as shown above if included.
*/
+ { "file_charset", DT_SYN, R_NONE, UL "attach_charset", 0 },
+ /*