[PATCH v2] Improve Windows build documentation

[Martin Bonner]

I have recently build the u-boot tools on Windows and ran into
difficulties.  This patch to the documentation would have avoided
those difficulties.  Contentious points:

* While I have run the document through a rst previewer, I haven't run
the full test suite.  I know, I know, everyone thinks _they_ don't
need to run the tests because reasons, but I think it's true this
time.
* I have removed the version numbers from the list of packages.  I
don't think they are helpful, and are just maintenance overhead.  (I
don't think I got those versions for example).

I'd be grateful if @Bin Meng could review this, because `git blame`
says the file I am changing is all his.

No actual changes, but hopefully closer to the required formalities:

Signed-off-by: Martin Bonner <martingreybeard at gmail.com>

commit e3615603d919ab19fddbee4a68e8a37b91a75f3e (HEAD ->
better-windows-build-doc)
Author: Martin Bonner <martingreybeard at gmail.com>
Date:   Tue Jul 5 09:10:59 2022 +0100

    Tweak docs for building tools on Windows

    * Add three more modules that are required.
    * Remove the version numbers (because they are hard to keep in sync)
    * Add a pacman command line to install everything.

diff --git a/doc/build/tools.rst b/doc/build/tools.rst
index c06f915274..95f1246617 100644
--- a/doc/build/tools.rst
+++ b/doc/build/tools.rst
@@ -24,14 +24,20 @@ you can use MSYS2, a software distro and building
platform for Windows.
 Download the MSYS2 installer from https://www.msys2.org. Make sure you have
 installed all required packages below in order to build these host tools::

-   * gcc (9.1.0)
-   * make (4.2.1)
-   * bison (3.4.2)
-   * diffutils (3.7)
-   * openssl-devel (1.1.1.d)
-
-Note the version numbers in these parentheses above are the package versions
-at the time being when writing this document. The MSYS2 installer tested is
+   * gcc
+   * make
+   * bison
+   * diffutils
+   * openssl-devel
+   * flex
+   * libgnutls-devel
+   * libuuid-devel
+
+You probably want ``git`` as well.  You can install all these with::
+
+    $ pacman -S gcc make bison diffutils openssl=devel flex
libgnutls-devel libuuid-devel git
+
+The MSYS2 installer tested is
 http://repo.msys2.org/distrib/x86_64/msys2-x86_64-20190524.exe.

 There are 3 MSYS subsystems installed: MSYS2, MinGW32 and MinGW64. Each

-- 

Martin