manual: use one-line titles instead of two-line titles (trivial)

Asciidoc supports two syntaxes for section titles: two-line titles (title
plus underline consisting of a particular symbol), and one-line titles
(title prefixed with a specific number of = signs).

The two-line title underlines are:
Level 0 (top level):     ======================
Level 1:                 ----------------------
Level 2:                 ~~~~~~~~~~~~~~~~~~~~~~
Level 3:                 ^^^^^^^^^^^^^^^^^^^^^^
Level 4 (bottom level):  ++++++++++++++++++++++

and the one-line title prefixes:
= Document Title (level 0) =
== Section title (level 1) ==

=== Section title (level 2) ===
==== Section title (level 3) ====
===== Section title (level 4) =====

The buildroot manual is currenly using the two-line titles, but this has
multiple disadvantages:

- asciidoc also uses some of the underline symbols for other purposes (like
  preformatted code, example blocks, ...), which makes it difficult to do
  mass replacements, such as a planned follow-up patch that needs to move
  all sections one level down.

- it is difficult to remember which level a given underline symbol (=-~^+)
  corresponds to, while counting = signs is easy.

This patch changes all two-level titles to one-level titles in the manual.
The bulk of the change was done with the following Python script, except for
the level 1 titles (-----) as these underlines are also used for literal
code blocks.
This patch only changes the titles, no other changes. In
adding-packages-directory.txt, I did add missing newlines between some
titles and their content.

----------------------------------------------------------------------------
#!/usr/bin/env python

import sys
import mmap
import re

for input in sys.argv[1:]:

    f = open(input, 'r+')
    f.flush()
    s = mmap.mmap(f.fileno(), 0)

    # Level 0 (top level):     ======================   =
    # Level 1:                 ----------------------   ==
    # Level 2:                 ~~~~~~~~~~~~~~~~~~~~~~   ===
    # Level 3:                 ^^^^^^^^^^^^^^^^^^^^^^   ====
    # Level 4 (bottom level):  ++++++++++++++++++++++   =====

    def replace_title(s, symbol, replacement):
        pattern = re.compile(r'(.+\n)\%s{2,}\n' % symbol, re.MULTILINE)
        return pattern.sub(r'%s \1' % replacement, s)

    new = s
    new = replace_title(new, '=', '=')
    new = replace_title(new, '+', '=====')
    new = replace_title(new, '^', '====')
    new = replace_title(new, '~', '===')
    #new = replace_title(new, '-', '==')

    s.seek(0)
    s.write(new)
    s.resize(s.tell())
    s.close()
    f.close()

----------------------------------------------------------------------------

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

1 files changed, 7 insertions, 14 deletions

diff --git a/docs/manual/adding-packages-virtual.txt b/docs/manual/adding-packages-virtual.txt
index c1b5a0a4ab..1c1116f2bc 100644
--- a/docs/manual/adding-packages-virtual.txt
+++ b/docs/manual/adding-packages-virtual.txt
@@ -1,8 +1,7 @@
 // -*- mode:doc; -*-
 // vim: set syntax=asciidoc:
 
-Infrastructure for virtual packages
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+=== Infrastructure for virtual packages
 
 [[virtual-package-tutorial]]
 
@@ -16,16 +15,14 @@ The implementation of this API is different for the 'Allwinner Tech Sunxi' and
 the 'Texas Instruments OMAP35xx' plaftorms. So +libgles+ will be a virtual
 package and +sunxi-mali+ and +ti-gfx+ will be the providers.
 
-+virtual-package+ tutorial
-^^^^^^^^^^^^^^^^^^^^^^^^^^
+==== +virtual-package+ tutorial
 
 In the following example, we will explain how to add a new virtual package
 ('something-virtual') and a provider for it ('some-provider').
 
 First, let's create the virtual package.
 
-Virtual package's +Config.in+ file
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+==== Virtual package's +Config.in+ file
 
 The +Config.in+ file of virtual package 'something-virtual' should contain:
 
@@ -42,8 +39,7 @@ In this file, we declare two options, +BR2_PACKAGE_HAS_SOMETHING_VIRTUAL+ and
 +BR2_PACKAGE_PROVIDES_SOMETHING_VIRTUAL+, whose values will be used by the
 providers.
 
-Virtual package's +*.mk+ file
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+==== Virtual package's +*.mk+ file
 
 The +.mk+ for the virtual package should just evaluate the +virtual-package+ macro:
 
@@ -60,8 +56,7 @@ The +.mk+ for the virtual package should just evaluate the +virtual-package+ mac
 The ability to have target and host packages is also available, with the
 +host-virtual-package+ macro.
 
-Provider's +Config.in+ file
-^^^^^^^^^^^^^^^^^^^^^^^^^^^
+==== Provider's +Config.in+ file
 
 When adding a package as a provider, only the +Config.in+ file requires some
 modifications. The +*.mk+ file should follow the Buildroot infrastructure with
@@ -92,8 +87,7 @@ provider, but only if it is selected.
 Of course, do not forget to add the proper build and runtime dependencies for
 this package!
 
-Notes on depending on a virtual package
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+==== Notes on depending on a virtual package
 
 When adding a package that requires a certain +FEATURE+ provided by a virtual
 package, you have to use +depends on BR2_PACKAGE_HAS_FEATURE+, like so:
@@ -107,8 +101,7 @@ config BR2_PACKAGE_FOO
     depends on BR2_PACKAGE_HAS_FEATURE
 ---------------------------
 
-Notes on depending on a specific provider
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+==== Notes on depending on a specific provider
 
 If your package really requires a specific provider, then you'll have to
 make your package +depends on+ this provider; you can _not_ +select+ a