net/mlx: fix build with make and recent gcc

[ upstream commit b38a54a ]

With VERBOSE=1, this error was seen in debug mode with gcc 9.1:

In file included from /tmp/dpdk.auto-config-h.sh.c.w0VWMi:1:
In file included from rdma-core/build/include/infiniband/mlx5dv.h:47:
In file included from rdma-core/build/include/infiniband/verbs.h:46:
In file included from rdma-core/build/include/infiniband/verbs_api.h:66:
In file included from rdma-core/build/include/infiniband/ib_user_ioctl_verbs.h:38:
include/rdma/ib_user_verbs.h:161:28: fatal error:
zero size arrays are an extension [-Wzero-length-array]
__aligned_u64 driver_data0;
^
1 error generated.

As a result, buildtools/auto-config-h.sh was not generating
a correct autoconf file, so the compilation was generating such error:

fatal error: redefinition of 'mlx5_ib_uapi_flow_action_packet_reformat_type'

It is fixed by disabling -pedantic option when calling auto-config-h.sh
from the makefile-based system.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Luca Boccassi <bluca@debian.org>
Acked-by: Matan Azrad <matan@mellanox.com>

drivers/net/mlx4/Makefile

@@ -65,6 +65,7 @@ endif
 # User-defined CFLAGS.
 ifeq ($(CONFIG_RTE_LIBRTE_MLX4_DEBUG),y)
 CFLAGS += -pedantic -UNDEBUG -DPEDANTIC
+AUTO_CONFIG_CFLAGS += -Wno-pedantic
 else
 CFLAGS += -DNDEBUG -UPEDANTIC
 endif
@@ -74,7 +75,7 @@ include $(RTE_SDK)/mk/rte.lib.mk
 # Generate and clean-up mlx4_autoconf.h.
 
 export CC CFLAGS CPPFLAGS EXTRA_CFLAGS EXTRA_CPPFLAGS
-export AUTO_CONFIG_CFLAGS = -Wno-error
+export AUTO_CONFIG_CFLAGS += -Wno-error
 
 ifndef V
 AUTOCONF_OUTPUT := >/dev/null

drivers/net/mlx5/Makefile

@@ -83,6 +83,7 @@ endif
 # User-defined CFLAGS.
 ifeq ($(CONFIG_RTE_LIBRTE_MLX5_DEBUG),y)
 CFLAGS += -pedantic -UNDEBUG -DPEDANTIC
+AUTO_CONFIG_CFLAGS += -Wno-pedantic
 else
 CFLAGS += -DNDEBUG -UPEDANTIC
 endif
@@ -92,7 +93,7 @@ include $(RTE_SDK)/mk/rte.lib.mk
 # Generate and clean-up mlx5_autoconf.h.
 
 export CC CFLAGS CPPFLAGS EXTRA_CFLAGS EXTRA_CPPFLAGS
-export AUTO_CONFIG_CFLAGS = -Wno-error
+export AUTO_CONFIG_CFLAGS += -Wno-error
 
 ifndef V
 AUTOCONF_OUTPUT := >/dev/null