[PATCH 1/1] tools build: Add a feature test for scandirat(), that is not implemented so far in musl and uclibc

[Arnaldo Carvalho de Melo]

We use it just when listing tracepoint events, and for root, so just
emit a warning about it to get users to ask the library maintainers to
implement it, as suggested in this systemd ticket:

 https://github.com/systemd/casync/issues/129

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/build/Makefile.feature   | 1 +
 tools/build/feature/Makefile   | 4 ++++
 tools/build/feature/test-all.c | 5 +++++
 tools/perf/Makefile.config     | 4 ++++
 4 files changed, 14 insertions(+)

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 214622d7537cc56b..934e2777a2dbcd90 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -64,6 +64,7 @@ FEATURE_TESTS_BASIC :=                  \
         lzma                            \
         get_cpuid                       \
         bpf                             \
+        scandirat			\
         sched_getcpu			\
         sdt				\
         setns				\
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 0a3b9281f8b08000..0f0aa9b7d7b5e43c 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -65,6 +65,7 @@ FILES=                                          \
          test-gettid.bin			\
          test-jvmti.bin				\
          test-jvmti-cmlr.bin			\
+         test-scandirat.bin			\
          test-sched_getcpu.bin			\
          test-setns.bin				\
          test-libopencsd.bin			\
@@ -129,6 +130,9 @@ $(OUTPUT)test-get_current_dir_name.bin:
 $(OUTPUT)test-glibc.bin:
 	$(BUILD)
 
+$(OUTPUT)test-scandirat.bin:
+	$(BUILD)
+
 $(OUTPUT)test-sched_getcpu.bin:
 	$(BUILD)
 
diff --git a/tools/build/feature/test-all.c b/tools/build/feature/test-all.c
index 957c02c7b163b579..6f4bf386a3b5c4b0 100644
--- a/tools/build/feature/test-all.c
+++ b/tools/build/feature/test-all.c
@@ -114,6 +114,10 @@
 # include "test-pthread-barrier.c"
 #undef main
 
+#define main main_test_scandirat
+# include "test-scandirat.c"
+#undef main
+
 #define main main_test_sched_getcpu
 # include "test-sched_getcpu.c"
 #undef main
@@ -206,6 +210,7 @@ int main(int argc, char *argv[])
 	main_test_get_cpuid();
 	main_test_bpf();
 	main_test_libcrypto();
+	main_test_scandirat();
 	main_test_sched_getcpu();
 	main_test_sdt();
 	main_test_setns();
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index dd203f0a2b7e64e1..16bea51f0bcd95ea 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -478,6 +478,10 @@ ifdef NO_DWARF
   NO_LIBDW_DWARF_UNWIND := 1
 endif
 
+ifeq ($(feature-scandirat), 1)
+  CFLAGS += -DHAVE_SCANDIRAT_SUPPORT
+endif
+
 ifeq ($(feature-sched_getcpu), 1)
   CFLAGS += -DHAVE_SCHED_GETCPU_SUPPORT
 endif
-- 
2.39.2