bpftool: Normalize compile rules to specify output file last

When dealing with verbose Makefile output, it's extremely confusing when
compiler invocation commands don't specify -o <output.o> as the last
argument. Normalize bpftool's Makefile to do just that, as most other
BPF-related Makefiles are already doing that.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211111053624.190580-2-andrii@kernel.org

tools/bpf/bpftool/Makefile

@@ -177,7 +177,8 @@ $(OUTPUT)%.bpf.o: skeleton/%.bpf.c $(OUTPUT)vmlinux.h $(LIBBPF)
 		-I$(if $(OUTPUT),$(OUTPUT),.) \
 		-I$(srctree)/tools/include/uapi/ \
 		-I$(LIBBPF_INCLUDE) \
-		-g -O2 -Wall -target bpf -c $< -o $@ && $(LLVM_STRIP) -g $@
+		-g -O2 -Wall -target bpf -c $< -o $@
+	$(Q)$(LLVM_STRIP) -g $@
 
 $(OUTPUT)%.skel.h: $(OUTPUT)%.bpf.o $(BPFTOOL_BOOTSTRAP)
 	$(QUIET_GEN)$(BPFTOOL_BOOTSTRAP) gen skeleton $< > $@
@@ -192,10 +193,10 @@ endif
 CFLAGS += $(if $(BUILD_BPF_SKELS),,-DBPFTOOL_WITHOUT_SKELETONS)
 
 $(BOOTSTRAP_OUTPUT)disasm.o: $(srctree)/kernel/bpf/disasm.c
-	$(QUIET_CC)$(HOSTCC) $(CFLAGS) -c -MMD -o $@ $<
+	$(QUIET_CC)$(HOSTCC) $(CFLAGS) -c -MMD $< -o $@
 
 $(OUTPUT)disasm.o: $(srctree)/kernel/bpf/disasm.c
-	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD -o $@ $<
+	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD $< -o $@
 
 $(OUTPUT)feature.o:
 ifneq ($(feature-zlib), 1)
@@ -203,17 +204,16 @@ ifneq ($(feature-zlib), 1)
 endif
 
 $(BPFTOOL_BOOTSTRAP): $(BOOTSTRAP_OBJS) $(LIBBPF_BOOTSTRAP)
-	$(QUIET_LINK)$(HOSTCC) $(CFLAGS) $(LDFLAGS) -o $@ $(BOOTSTRAP_OBJS) \
-		$(LIBS_BOOTSTRAP)
+	$(QUIET_LINK)$(HOSTCC) $(CFLAGS) $(LDFLAGS) $(BOOTSTRAP_OBJS) $(LIBS_BOOTSTRAP) -o $@
 
 $(OUTPUT)bpftool: $(OBJS) $(LIBBPF)
-	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(OBJS) $(LIBS)
+	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $(OBJS) $(LIBS) -o $@
 
 $(BOOTSTRAP_OUTPUT)%.o: %.c $(LIBBPF_INTERNAL_HDRS) | $(BOOTSTRAP_OUTPUT)
-	$(QUIET_CC)$(HOSTCC) $(CFLAGS) -c -MMD -o $@ $<
+	$(QUIET_CC)$(HOSTCC) $(CFLAGS) -c -MMD $< -o $@
 
 $(OUTPUT)%.o: %.c
-	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD -o $@ $<
+	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD $< -o $@
 
 feature-detect-clean:
 	$(call QUIET_CLEAN, feature-detect)