tools feature: Add support for detecting libpfm4

libpfm4 provides an alternate command line encoding of perf events.

Signed-off-by: Stephane Eranian <[e-mail]>
Reviewed-by: Ian Rogers <[e-mail]>
Acked-by: Jiri Olsa <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Alexei Starovoitov <[e-mail]>
Cc: Alexey Budankov <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: Andrii Nakryiko <[e-mail]>
Cc: Daniel Borkmann <[e-mail]>
Cc: Florian Fainelli <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Igor Lubashev <[e-mail]>
Cc: Jin Yao <[e-mail]>
Cc: Jiwei Sun <[e-mail]>
Cc: John Garry <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Leo Yan <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Martin KaFai Lau <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Yonghong Song <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: yuzhoujian <[e-mail]>
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/build/Makefile.feature

···
          llvm                           \
          llvm-version                   \
          clang                          \
-         libbpf
+         libbpf                         \
+         libpfm4
 
 FEATURE_TESTS ?= $(FEATURE_TESTS_BASIC)
 

tools/build/feature/Makefile

···
          test-libaio.bin			\
          test-libzstd.bin			\
          test-clang-bpf-global-var.bin		\
-         test-file-handle.bin
+         test-file-handle.bin			\
+         test-libpfm4.bin
 
 FILES := $(addprefix $(OUTPUT),$(FILES))
 
···
 
 $(OUTPUT)test-file-handle.bin:
 	$(BUILD)
+
+$(OUTPUT)test-libpfm4.bin:
+	$(BUILD) -lpfm
 
 ###############################
 

tools/build/feature/test-libpfm4.c

···
+// SPDX-License-Identifier: GPL-2.0
+#include <sys/types.h>
+#include <perfmon/pfmlib.h>
+
+int main(void)
+{
+	pfm_initialize();
+	return 0;
+}