Similar to commit 835a50753579 ("selftests/bpf: Add -fms-extensions to
bpf build flags") and commit 639f58a0f480 ("bpftool: Fix build warnings
due to MS extensions")

The kernel is now built with -fms-extensions, therefore
generated vmlinux.h contains types like:
struct slab {
   ..
   struct freelist_counters;
};

Use -fms-extensions and -Wno-microsoft-anon-tag flags
to build bpf programs that #include "vmlinux.h"

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
---
 drivers/hid/bpf/progs/Makefile | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/bpf/progs/Makefile b/drivers/hid/bpf/progs/Makefile
index ec1fc642fd63..66b8f38e591d 100644
--- a/drivers/hid/bpf/progs/Makefile
+++ b/drivers/hid/bpf/progs/Makefile
@@ -56,8 +56,10 @@ clean:
 
 %.bpf.o: %.bpf.c vmlinux.h $(BPFOBJ) | $(OUTPUT)
 	$(call msg,BPF,$@)
-	$(Q)$(CLANG) -g -O2 --target=bpf -Wall -Werror $(INCLUDES)	      \
-		 -c $(filter %.c,$^) -o $@ &&				      \
+	$(Q)$(CLANG) -g -O2 --target=bpf -Wall -Werror $(INCLUDES)		\
+		     -Wno-microsoft-anon-tag					\
+		     -fms-extensions						\
+		     -c $(filter %.c,$^) -o $@ &&				\
 	$(LLVM_STRIP) -g $@
 
 vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) | $(INCLUDE_DIR)

-- 
2.52.0