acinclude: Remove default library for DPDK.

The default DPDK library used before this patch in case pkg-config
fails to find libdpdk is only valid for make based DPDK builds.
Hence remove them.

As a consequence, now this error message [1] is thrown when pkg-config
cannot find libdpdk instead of proceeding to check for a faulty
pkg-config and reporting incorrect error message [2].

Also, update the documentation to export PKG_CONFIG_PATH since on some
systems, the default install path for DPDK libraries is not present in
the default search path of pkg-config.
Ex: for Fedora 32 default pkg-config search path:
  /usr/lib64/pkgconfig:/usr/share/pkgconfig

while by default Meson installs DPDK libraries at:
  /usr/local/lib64/pkgconfig

[1] Package libdpdk was not found in the pkg-config search path.
    Perhaps you should add the directory containing `libdpdk.pc'
    to the PKG_CONFIG_PATH environment variable
    Package 'libdpdk', required by 'virtual:world', not found

[2] checking for DPDK... no
    checking for faulty pkg-config version... yes
    configure: error: Please upgrade pkg-config

Also, update the build documentation for AVX512 optimization.

Fixes: 252e1e576443 ("dpdk: Update to use DPDK v20.11.")
Reported-by: Kevin Traynor <ktraynor@redhat.com>
Acked-by: Kevin Traynor <ktraynor@redhat.com>
Signed-off-by: Sunil Pai G <sunil.pai.g@intel.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

0 files changed, 0 insertions, 0 deletions