[dpdk-dev] Build failures in 21.11-rc2

[Lance Richardson <lance.richardson@broadcom.com>]

21.11-rc2 builds are failing on CentOS 8.4, apparently because
the intrinsic _mm512_set_epi8() is not defined in the GCC
headers (see example below).

Perhaps code using _mm512_set_epi8() could be reworked to
avoid that intrinsic, or maybe support could be detected at build
configuration time and definitions for them could be provided in
DPDK headers.

Here is a GCC patch to add this intrinsic:
https://www.mail-archive.com/gcc-patches@gcc.gnu.org/msg188664.html

BTW, GCC 10.2.1 (via "scl enable gcc-toolset-10") is able to build
21.11-rc2 successfully on CentOS 8.4.

    Lance

# gcc --version
gcc (GCC) 8.4.1 20200928 (Red Hat 8.4.1-1)
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

In file included from ../lib/hash/rte_thash_gfni.h:16,
                 from ../lib/hash/rte_thash.h:27,
                 from ../lib/hash/rte_thash.c:7:
../lib/hash/rte_thash_x86_gfni.h: In function ‘__rte_thash_gfni’:
../lib/hash/rte_thash_x86_gfni.h:59:24: error: implicit declaration of
function ‘_mm512_set_epi8’; did you mean ‘_mm512_set1_epi8’?
[-Werror=implicit-function-declaration]
  __m512i permute_idx = _mm512_set_epi8(7, 6, 5, 4, 7, 6, 5, 4,
                        ^~~~~~~~~~~~~~~
                        _mm512_set1_epi8