[PATCH] trace: fix build with clang 21

[David Marchand]

This was caught with recent clang.
The RTE_TRACE_POINT_ARGS() macro expects at least one parameter.
As a (void) function does not require any special tweaking with
__rte_unused, we can simply replace with a direct (void) token.

Build dir: /export/dpdk-next-net-mrvl/build-clang-static
Project version: 25.11.0-rc1
C compiler for the host machine: ccache clang (clang 21.1.4
	"clang version 21.1.4")

In file included from ../lib/eal/common/eal_common_trace_points.c:7:
../lib/eal/include/rte_eal_trace.h:23:2: error: attribute 'unused'
	cannot be applied to a 'void' parameter
	[-Werror,-Wignored-attributes]
   23 |         RTE_TRACE_POINT_ARGS(void),
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
../lib/eal/include/rte_trace_point_register.h:46:3: note: expanded
	from macro 'RTE_TRACE_POINT_ARGS'
   46 |         (RTE_TRACE_POINT_ARGS_(RTE_TRACE_POINT_ARGS_COUNT(0,
	__VA_ARGS__), __VA_ARGS__))
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	~~~~~~~~~~~~~~~~~~~~~~~~~~~
../lib/eal/include/rte_trace_point_register.h:44:30: note: expanded
	from macro 'RTE_TRACE_POINT_ARGS_'
   44 |         RTE_TRACE_POINT_ARGS_EXPAND(RTE_TRACE_POINT_ARGS_FUNC
	(N))(__VA_ARGS__)
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
	~~~~~~~~~~~~~~~~~
../lib/eal/include/rte_trace_point_register.h:41:38: note: expanded
	from macro 'RTE_TRACE_POINT_ARGS_FUNC'
   41 | #define RTE_TRACE_POINT_ARGS_FUNC(a) RTE_TRACE_POINT_ARGS_ ## a
      |                                      ^
note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0
	to see all)
../lib/eal/include/rte_trace_point_register.h:42:42: note: expanded
	from macro 'RTE_TRACE_POINT_ARGS_EXPAND'
   42 | #define RTE_TRACE_POINT_ARGS_EXPAND(...) __VA_ARGS__
      |                                          ^
../lib/eal/include/rte_trace_point_register.h:26:35: note: expanded
	from macro 'RTE_TRACE_POINT_ARGS_1'
   26 | #define RTE_TRACE_POINT_ARGS_1(a) __rte_unused a
      |                                   ^~~~~~~~~~~~
../lib/eal/include/rte_common.h:248:37: note: expanded
	from macro '__rte_unused'
  248 | #define __rte_unused __attribute__((__unused__))
      |                                     ^~~~~~~~~~
1 error generated.

Cc: stable at dpdk.org

Reported-by: Jerin Jacob <jerinj at marvell.com>
Signed-off-by: David Marchand <david.marchand at redhat.com>
---
 app/test/test_trace.h           | 2 +-
 lib/eal/include/rte_eal_trace.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/app/test/test_trace.h b/app/test/test_trace.h
index 4ad44e2bea..123ec8290a 100644
--- a/app/test/test_trace.h
+++ b/app/test/test_trace.h
@@ -13,5 +13,5 @@ RTE_TRACE_POINT(
 
 RTE_TRACE_POINT_FP(
 	app_dpdk_test_fp,
-	RTE_TRACE_POINT_ARGS(void),
+	(void),
 )
diff --git a/lib/eal/include/rte_eal_trace.h b/lib/eal/include/rte_eal_trace.h
index 9ad2112801..152474bf84 100644
--- a/lib/eal/include/rte_eal_trace.h
+++ b/lib/eal/include/rte_eal_trace.h
@@ -20,7 +20,7 @@ extern "C" {
 /* Generic */
 RTE_TRACE_POINT(
 	rte_eal_trace_generic_void,
-	RTE_TRACE_POINT_ARGS(void),
+	(void),
 )
 
 RTE_TRACE_POINT(
-- 
2.51.0