include/bpf.mk: preserve the bpf .o file with debug symbols

Makes it easier to analyze verifier complaints

Signed-off-by: Felix Fietkau <nbd@nbd.name>

include/bpf.mk

@@ -77,6 +77,7 @@ define CompileBPF
 	$(LLVM_OPT) -O2 -mtriple=$(BPF_TARGET) < $(patsubst %.c,%.bc,$(1)) > $(patsubst %.c,%.opt,$(1))
 	$(LLVM_DIS) < $(patsubst %.c,%.opt,$(1)) > $(patsubst %.c,%.S,$(1))
 	$(LLVM_LLC) -march=$(BPF_TARGET) -filetype=obj -o $(patsubst %.c,%.o,$(1)) < $(patsubst %.c,%.S,$(1))
+	$(CP) $(patsubst %.c,%.o,$(1)) $(patsubst %.c,%.debug.o,$(1))
 	$(LLVM_STRIP) --strip-debug $(patsubst %.c,%.o,$(1))
 endef