editors: only extend line width to 119 for C and XML files

For all other files leave the line width at 79 as before. This is a good idea
since we generally don't want text files such as catalog files, unit files or
README/NEWS files to be line-broken at 119 since they are regularly browsed on
text terminals.

While we are at it, also add a couple of comments to the various files.

(Note that .editorconfig doesn't carry line-width information, simply because
the specification doesn't know the concept.)

.dir-locals.el

@@ -2,13 +2,22 @@
 ; A list of (major-mode . ((var1 . value1) (var2 . value2)))
 ; Mode can be nil, which gives default values.
 
+; Note that we set a line width of 119 for .c and XML files, but for everything
+; else (such as journal catalog files, unit files, README files) we stick to a
+; more conservative 79 characters.
+
+; NOTE: If you update this file make sure to update .vimrc and .editorconfig,
+; too.
+
 ((nil . ((indent-tabs-mode . nil)
          (tab-width . 8)
-         (fill-column . 119)))
- (c-mode . ((c-basic-offset . 8)
+         (fill-column . 79)))
+ (c-mode . ((fill-column . 119)
+            (c-basic-offset . 8)
             (eval . (c-set-offset 'substatement-open 0))
             (eval . (c-set-offset 'statement-case-open 0))
             (eval . (c-set-offset 'case-label 0))
             (eval . (c-set-offset 'arglist-intro '++))
             (eval . (c-set-offset 'arglist-close 0))))
- (nxml-mode . ((nxml-child-indent . 2))))
+ (nxml-mode . ((nxml-child-indent . 2)
+               (fill-column . 119))))

.editorconfig

@@ -1,7 +1,10 @@
 # EditorConfig configuration for systemd
 # http://EditorConfig.org
 
-# top-most EditorConfig file
+# NOTE: If you update this file make sure to update .dir-locals.el and .vimrc,
+# too.
+
+# Top-most EditorConfig file
 root = true
 
 # Unix-style newlines with a newline ending every file, utf-8 charset
@@ -11,7 +14,7 @@ insert_final_newline = true
 trim_trailing_whitespace = true
 charset = utf-8
 
-# match config files, set indent to spaces with width of eight
+# Match config files, set indent to spaces with width of eight
 [*.{c,h}]
 indent_style = space
 indent_size = 8

.vimrc

@@ -3,8 +3,18 @@
 " vimrc configuration file, including write operations and shell execution.
 " You should consider setting 'set secure' as well, which is highly
 " recommended!
+
+" Note that we set a line width of 119 for .c and XML files, but for everything
+" else (such as journal catalog files, unit files, README files) we stick to a
+" more conservative 79 characters.
+
+" NOTE: If you update this file make sure to update .dir-locals.el and
+" .editorconfig, too.
+
 set tabstop=8
 set shiftwidth=8
 set expandtab
 set makeprg=GCC_COLORS=\ make
-set tw=119
+set tw=79
+au FileType xml set tw=119
+au FileType c set tw=119

catalog/systemd.catalog

@@ -1,4 +1,3 @@
-# -*- fill-column: 79; indent-tabs-mode: nil -*-
 #  This file is part of systemd.
 #
 #  Copyright 2012 Lennart Poettering