RE: [PATCH] meson: update doc logic for Windows

["Varghese, Vipin" <Vipin.Varghese@amd.com>]

[AMD Official Use Only]

Hi Dmitry,

Thanks for inputs, please find my question below

<snip>

2022-03-28 03:02 (UTC+0000), Varghese, Vipin:
> [AMD Official Use Only]
>
> Hi Thomas,
>
> <snipp>
>
> Thank you for looking at this problem.
>
> 26/03/2022 03:59, Vipin Varghese:
> > Support for shell scripts doxy-html-custom, generate_doxygen and 
> > generate_examples are absent. The current patch address the same by 
> > disabling document build notifying the user.
>
> It should not prevent generating guides with sphinx.
>
> We did get error from `doc/meson` stating ` echo command not available 
> on windows` for both cmd and powershell for the line ``` 
> run_target('doc', command: [echo, message, doc_target_names],
>     depends: doc_targets)
> ```

This line never searches for "echo" command, e8c90926bdde ("doc: fix build on Windows with Meson 0.58") introduced "echo" variable precisely to avoid this.
Can you give the full log?

> > Steps to reproduce the error:
> >  - Install dependencies doxygen & sphinix build on Windwos server 2019.
> >  - Build DPDK with option enable_docs=true for API or User Guide.
> >
> > This produces error
> > ```
> > FAILED: doc/api/examples.dox
> > sh -e dpdk/doc/api/generate_examples.sh dpdk/examples 
> > doc/api/examples.dox ```
>
> I suppose we could replace shell scripts with Python equivalent.
>
> I am trying to minimize the changes as first step: fix the build error by disabling on windows`.
> Next step we can convert to python to make it cross platform independent.

If something is explicitly requested but not supported, there should be a failure.
By the way, -Denable_docs=true works when cross-compiling for Windows, so disabling docs for this target is not right.
I think we should sort out what's causing an issue with "echo" for you (it shouldn't happen), then fix the scripts to fully enable docs.

Are you recommending 

Windows libraries and binaries should be cross build from linux (where all dependencies and shell script works)?

Or 

let us enhance the check for windows native build, if yes for option `-Denable_docs=true, we can stop the build for docs`.

If the latter is suggestion I will share v2 patch to check the same.