build: use DPDK_MACHINE=haswell when testing dpdk build on github-hos…

…ted runner

when building dpdk on a building host which has AVX10.1 ISA support,
with Clang 18, we have following failure
```
/usr/lib/llvm-18/bin/clang -Ilib/net/libnet_crc_avx512_lib.a.p -Ilib/net -I../../../../../../dpdk/lib/net -I. -I../../../../../../dpdk -Iconfig -I../../../../../../dpdk/config -Ilib/eal/include -I../../../../../../dpdk/lib/eal/include -Ilib/eal/linux/include -I../../../../../../dpdk/lib/eal/linux/include -Ilib/eal/x86/include -I../../../../../../dpdk/lib/eal/x86/include -Ilib/eal/common -I../../../../../../dpdk/lib/eal/common -Ilib/eal -I../../../../../../dpdk/lib/eal -Ilib/kvargs -I../../../../../../dpdk/lib/kvargs -Ilib/metrics -I../../../../../../dpdk/lib/metrics -Ilib/telemetry -I../../../../../../dpdk/lib/telemetry -fcolor-diagnostics -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -O3 -include rte_config.h -Wcast-qual -Wdeprecated -Wformat -Wformat-nonliteral -Wformat-security -Wmissing-declarations -Wmissing-prototypes -Wnested-externs -Wold-style-definition -Wpointer-arith -Wsign-compare -Wstrict-prototypes -Wundef -Wwrite-strings -Wno-address-of-packed-member -Wno-missing-field-initializers -D_GNU_SOURCE -Wno-error -fPIC -march=native -DALLOW_EXPERIMENTAL_API -DALLOW_INTERNAL_API -Wno-format-truncation -DCC_X86_64_SSE42_PCLMULQDQ_SUPPORT -DCC_X86_64_AVX512_VPCLMULQDQ_SUPPORT -mavx512f -mavx512bw -mavx512dq -mavx512vl -mvpclmulqdq -mavx2 -mavx -MD -MQ lib/net/libnet_crc_avx512_lib.a.p/net_crc_avx512.c.o -MF lib/net/libnet_crc_avx512_lib.a.p/net_crc_avx512.c.o.d -o lib/net/libnet_crc_avx512_lib.a.p/net_crc_avx512.c.o -c ../../../../../../dpdk/lib/net/net_crc_avx512.c
Error: ../../../../../../dpdk/lib/net/net_crc_avx512.c:324:22: error: always_inline function '_mm512_broadcast_i32x4' requires target feature 'evex512', but would be inlined into function 'crc32_load_init_constants' that is compiled without support for 'evex512'
  324 |         crc32_eth.rk1_rk2 = _mm512_broadcast_i32x4(a);
      |                             ^
```

according to https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html
and
https://github.com/llvm/llvm-project/blob/release/18.x/clang/docs/UsersManual.rst#x86,
we should either use `-mevex512` or use `-mavx10.1-512` for accessing
these new vectorized instructions provided by AVX10.1. but we also
pass "-march=native" to the compiler. it turns out that at least some
github-hosted runners do not support AVX10.1 ISA, but the Clang 18
compiler does. so this combination breaks the build, as dpdk tries
to check if compiler supports AVX512, and if it does, dpdk builds
the AVX512 C files with this unsupported combination. that's why we
have build failures recently.

to address this issue, instead of using "native" as the value of
`Seastar_DPDK_MACHINE`, let's use a more conservative but still
capable architecture supported by github-hosted runner: "haswell",
which supports the instruction set that is used by quite a few
DPDK optimizations. so we can still have a decent coverage for
building with DPDK, and for testing the build. please note,
we don't test Seastar with the DPDK backend yet.

Fixes scylladb#2242

Signed-off-by: Kefu Chai <[email protected]>

.github/workflows/tests.yaml

@@ -98,6 +98,7 @@ jobs:
           --compiler $CXX
           --c-compiler $CC
           --mode ${{ matrix.mode }}
+          --cflags "-march=haswell"
           ${{ matrix.cooks }}
           ${{ matrix.enables }} ;