updated ebpf makefile

 - Added -fno-stack-protector:
   https://lore.kernel.org/bpf/194f38f2dc7d521375e5a660baaf1be31536be9a.camel@gmail.com/
   https://reviews.llvm.org/D142046

 - Added -Wno-unused-value, -Wunused to warn on unitialized/not used
   variables.

kudos to @planetoryd for reporting this (#1080).

ebpf_prog/Makefile

@@ -43,9 +43,13 @@ CLANG_FLAGS = -I. \
 	-D__KERNEL__ -D__BPF_TRACING__ -Wno-unused-value -Wno-pointer-sign \
 	-D__TARGET_ARCH_$(ARCH) -Wno-compare-distinct-pointer-types \
 	$(EXTRA_FLAGS) \
+	-Wunused \
+	-Wno-unused-value \
 	-Wno-gnu-variable-sized-type-not-at-end \
-	-Wno-address-of-packed-member -Wno-tautological-compare \
+	-Wno-address-of-packed-member \
+	-Wno-tautological-compare \
 	-Wno-unknown-warning-option  \
+	-fno-stack-protector \
 	-g -O2 -emit-llvm
 
 all: $(BIN)