[PATCH v2] build: add definitions for use as meson subproject

[Bruce Richardson]

On Fri, Nov 05, 2021 at 10:22:13AM -0700, Stephen Hemminger wrote:
> Some other projects using meson may not be able to use DPDK
> using the standard distribution pkg-config mechanism.
> Meson supports a way to handle this via the subproject
>   https://mesonbuild.com/Subprojects.html
> 
> This patch adds the necessary dependency to follow the
> "Naming convention for dependency variables" from the documentation.
> 
> Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
> ---
> 
> v2 - add link libraries
> 
Playing around with DPDK as a meson subproject myself, I have some
additional thoughts on how to put this in DPDK and some further comments on
this patch. For example:

* For static builds we need to "link_whole" the drivers, as well as doing a
  "link_with" on the libraries
* for shared builds - which will need to be done explicitly by passing the
  subproject the default_library type parameter we actually don't need to
  include the "link_with" line since the libs are already included in the
  shared deps. [I think they should be added to the static deps too, if
  that doesn't cause any problems]
* we therefore likely need slightly different subproject definitions for
  shared vs static, and I'd suggest moving that to a new file e.g. in
  "buildtools/subproject" - to avoid cluttering the main file too much.

If you don't mind, I'll do a re-spin of this functionality in a
V3 patch, based on above ideas, and we can see where we go there.

/Bruce