[RFC PATCH 10/20] tools/build: Add a feature test for bpftool-btf

[Gabriele Monaco <gmonaco@redhat.com>]

RV can run bpf monitors and also build them, only the latter requires
the vmlinux.h from bpftool btf.

Add a feature so that RV can be built with BPF support without having to
build in-tree BPF monitors if not supported on the system.

Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
 tools/build/Makefile.feature | 1 +
 tools/build/feature/Makefile | 7 ++++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 99eb0ea09537..18e3a7ae893a 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -129,6 +129,7 @@ FEATURE_TESTS_EXTRA :=                  \
          libdebuginfod			\
          clang-bpf-co-re		\
          bpftool-skeletons		\
+         bpftool-btf			\
          libunwind			\
          libunwind-debug-frame		\
          $(foreach arch,$(LIBUNWIND_ARCHS),libunwind-$(arch) libunwind-debug-frame-$(arch))
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 7d165018116a..2f01203dda5c 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -71,7 +71,8 @@ FILES=                                          \
          test-libpfm4.bin			\
          test-rust.bin				\
          test-libopenssl.bin			\
-         test-bpftool-skeletons.bin
+         test-bpftool-skeletons.bin		\
+         test-bpftool-btf.bin
 
 FILES := $(addprefix $(OUTPUT),$(FILES))
 
@@ -383,6 +384,10 @@ $(OUTPUT)test-bpftool-skeletons.bin:
 	{ $(SYSTEM_BPFTOOL) version | grep '^features:.*skeletons'; } \
 		> $(@:.bin=.make.output) 2>&1 && touch $@
 
+$(OUTPUT)test-bpftool-btf.bin:
+	$(SYSTEM_BPFTOOL) btf help \
+		> $(@:.bin=.make.output) 2>&1 && touch $@
+
 # Testing Rust is special: we don't compile anything, it's enough to check the
 # compiler presence. Compiling a test code for this purposes is problematic,
 # because Rust will emit a dependency file without any external references,
-- 
2.55.0