[Buildroot] [PATCH 1/1] manual: add patch revision and versioning section

[Vinicius Tinti]

Improve the contribute manual section by adding an explanation about patch
review and version.

The section now provides advices in how to respond mantainers requests and how
to proceed on replying them.

Signed-off-by: Vinicius Tinti <viniciustinti at gmail.com>
---
 docs/manual/contribute.txt |   51 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/docs/manual/contribute.txt b/docs/manual/contribute.txt
index 0106df0..2bdfc37 100644
--- a/docs/manual/contribute.txt
+++ b/docs/manual/contribute.txt
@@ -62,6 +62,57 @@ Make sure posted *patches are not line-wrapped*, otherwise they cannot
 easily be applied. In such a case, fix your e-mail client, or better,
 use +git send-email+ to send your patches.
 
+Patch revision
+^^^^^^^^^^^^^^
+
+Hardly ever some revisions will be requested to your patch. Whenever
+it happens make sure to always reply in the same thread and include
+the changes that have made.
+
+Revisions must describe which changes they include. When editing your
+commit, below the +signed-off-by+ section, add +---+ and your changes.
++git+ will automatically ignore lines below +---+ which will not be merged
+on upstream but will be present for reviewers. For longer series, the
+changelog should be placed in each commit and the cover letter must contain
+a summary of these changes. The following suggested layout example
+is not mandatory.
+
+---------------
+<topic on one line of less than ~80 characters>
+<empty newline>
+<more paragraphs describing what it is doing and why>
+<empty newline>
+Signed-off-by John Doe <john.doe at noname.org>
+---
+Changes v2 -> v3:
+  - foo bar  (Jane)
+  - bar buz
+Changes v1 -> v2:
+  - alpha bravo  (John)
+  - charly delta
+---------------
+
+Any patch revision must include the version number. The version number
+is simply composed by the letter +v+ followed by an +integer+ greater or
+equal 2 (two) (i.e. PATCH v2, PATCH v3 ...).
+
+This can be easly handle in +git-format-patch+ command by using the option
++--subject-prefix+:
+
+---------------------
+ $ git format-patch --subject-prefix "PATCH v4" -M -n -s -o outgoing origin/master
+---------------------
+
+Mail clients will handle this automatically reply in the same thread but
++git+ won't. Hence the +--in-reply-to+ option in +git-send-email+ must
+be used. Get the last +Message-ID+ (it can be found your mail client by
+accessing the raw mail). Then use this message id to send your revision
+patch:
+
+---------------------
+ $ git send-email --to buildroot at busybox.net --in-reply-to mymsgid at noname.org outgoing/*
+---------------------
+
 Reviewing/Testing patches
 -------------------------
 
-- 
1.7.9.5