[dpdk-dev] [RFC] build: allow build DPDK as a meson submodule

[Stephen Hemminger <stephen@networkplumber.org>]

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 depedency to follow the
"Naming convention for depedency variables" from the documentation.
It has no impact if subproject is not being used.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 meson.build | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/meson.build b/meson.build
index 12cb6e0e83f3..6ce5eda2779f 100644
--- a/meson.build
+++ b/meson.build
@@ -97,6 +97,16 @@ configure_file(output: build_cfg,
 # build pkg-config files for dpdk
 subdir('buildtools/pkg-config')
 
+# If DPDK is being built as subproject then define
+# varialble with the dependency convention
+if meson.is_subproject()
+    libdpdk_dep = declare_dependency(
+        version: meson.project_version(),
+        compile_args : pkg_extra_cflags,
+        dependencies: shared_deps
+    )
+endif
+
 # final output, list all the libs and drivers to be built
 # this does not affect any part of the build, for information only.
 output_message = '\n=================\nLibraries Enabled\n=================\n'
-- 
2.30.2