build-sys: pass CFLAGS & LDFLAGS to subdir-slirp

CFLAGS/LDFLAGS have debug and sanitizers flags, which should be passed
to slirp compilation.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20190424110041.8175-2-marcandre.lureau@redhat.com>
Signed-off-by: NSamuel Thibault <samuel.thibault@ens-lyon.org>

Makefile

@@ -480,7 +480,7 @@ subdir-capstone: .git-submodule-status
 	$(call quiet-command,$(MAKE) -C $(SRC_PATH)/capstone CAPSTONE_SHARED=no BUILDDIR="$(BUILD_DIR)/capstone" CC="$(CC)" AR="$(AR)" LD="$(LD)" RANLIB="$(RANLIB)" CFLAGS="$(CAP_CFLAGS)" $(SUBDIR_MAKEFLAGS) $(BUILD_DIR)/capstone/$(LIBCAPSTONE))
 
 subdir-slirp: .git-submodule-status
-	$(call quiet-command,$(MAKE) -C $(SRC_PATH)/slirp BUILD_DIR="$(BUILD_DIR)/slirp" CC="$(CC)" AR="$(AR)" LD="$(LD)" RANLIB="$(RANLIB)" CFLAGS="$(QEMU_CFLAGS)")
+	$(call quiet-command,$(MAKE) -C $(SRC_PATH)/slirp BUILD_DIR="$(BUILD_DIR)/slirp" CC="$(CC)" AR="$(AR)" LD="$(LD)" RANLIB="$(RANLIB)" CFLAGS="$(QEMU_CFLAGS) $(CFLAGS)" LDFLAGS="$(LDFLAGS)")
 
 $(SUBDIR_RULES): libqemuutil.a $(common-obj-y) $(chardev-obj-y) \
 	$(qom-obj-y) $(crypto-aes-obj-$(CONFIG_USER_ONLY))