dkms build fails

[bacon-cheeseburger]

Hi. Just got a TP-Link Archer T4U (v3). I'm running Debian Sid with stable kernel 5.2.11. GCC 4:8.3.0-1. Following the dkms instructions, the build fails with the errors below.

$ sudo dkms build -m rtl88x2bu -v ${VER}

Kernel preparation unnecessary for this kernel. Skipping...

Building module:
cleaning build area...
make -j2 KERNELRELEASE=5.2.11-amd KVER=5.2.11-amd src=/usr/src/rtl88x2bu-5.3.1............................(bad exit status: 2)
Error! Bad return status for module build on kernel: 5.2.11-amd (i686)
Consult /var/lib/dkms/rtl88x2bu/5.3.1/build/make.log for more information.

$ cat /var/lib/dkms/rtl88x2bu/5.3.1/build/make.log
DKMS make.log for rtl88x2bu-5.3.1 for kernel 5.2.11-amd (i686)
Thu 05 Sep 2019 07:29:46 PM PDT
make ARCH=i386 CROSS_COMPILE= -C /lib/modules/5.2.11-amd/build M=/var/lib/dkms/rtl88x2bu/5.3.1/build modules
make[1]: Entering directory '/usr/src/linux-headers-5.2.11-amd'
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_cmd.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_security.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_debug.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_io.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_ioctl_query.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_ioctl_set.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_ieee80211.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_mlme.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_mlme_ext.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_mi.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_wlan_util.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_vht.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_pwrctrl.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_rf.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_recv.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_sta_mgt.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_ap.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/mesh/rtw_mesh.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/mesh/rtw_mesh_pathtbl.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/mesh/rtw_mesh_hwmp.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_xmit.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_p2p.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_rson.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_tdls.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_br_ext.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_iol.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_sreset.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_btcoex_wifionly.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_btcoex.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_beamforming.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_odm.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_rm.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_rm_fsm.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/efuse/rtw_efuse.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/osdep_service.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/linux/os_intfs.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/linux/usb_intf.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/linux/usb_ops_linux.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/linux/ioctl_linux.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/linux/xmit_linux.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/linux/mlme_linux.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/linux/recv_linux.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/linux/ioctl_cfg80211.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/linux/rtw_cfgvendor.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/linux/wifi_regd.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/linux/rtw_android.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/linux/rtw_proc.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/linux/rtw_rhashtable.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/os_dep/linux/ioctl_mp.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/hal_intf.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/hal_com.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/hal_com_phycfg.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/hal_phy.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/hal_dm.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/hal_dm_acs.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/hal_btcoex_wifionly.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/hal_btcoex.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/hal_mp.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/hal_mcc.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/hal_hci/hal_usb.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/led/hal_led.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/led/hal_usb_led.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/hal_halmac.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/rtl8822b/rtl8822b_halinit.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/rtl8822b/rtl8822b_mac.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/rtl8822b/rtl8822b_cmd.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/rtl8822b/rtl8822b_phy.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/rtl8822b/rtl8822b_ops.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/rtl8822b/hal8822b_fw.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/rtl8822b/usb/rtl8822bu_halinit.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/rtl8822b/usb/rtl8822bu_halmac.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/rtl8822b/usb/rtl8822bu_io.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/rtl8822b/usb/rtl8822bu_xmit.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/rtl8822b/usb/rtl8822bu_recv.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/rtl8822b/usb/rtl8822bu_led.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/rtl8822b/usb/rtl8822bu_ops.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/efuse/rtl8822b/HalEfuseMask8822B_USB.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_api.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_bb_rf_88xx.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_cfg_wmac_88xx.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_common_88xx.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_efuse_88xx.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_flash_88xx.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_fw_88xx.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_gpio_88xx.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_init_88xx.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_mimo_88xx.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_pcie_88xx.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_sdio_88xx.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_usb_88xx.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_8822b/halmac_cfg_wmac_8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_8822b/halmac_common_8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_8822b/halmac_gpio_8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_8822b/halmac_init_8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_8822b/halmac_pcie_8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_8822b/halmac_phy_8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_8822b/halmac_pwr_seq_8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_8822b/halmac_sdio_8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/halmac/halmac_88xx/halmac_8822b/halmac_usb_8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_debug.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_antdiv.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_soml.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_smt_ant.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_antdect.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_interface.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_phystatus.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_hwconfig.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_dig.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_pathdiv.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_rainfo.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_dynamictxpower.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_adaptivity.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_cfotracking.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_noisemonitor.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_beamforming.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_dfs.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/txbf/halcomtxbf.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/txbf/haltxbfinterface.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/txbf/phydm_hal_txbf_api.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_adc_sampling.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_ccx.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_psd.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_primary_cca.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_cck_pd.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_rssi_monitor.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_auto_dbg.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_math_lib.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_api.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/phydm_pow_train.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/halrf/halrf.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/halrf/halphyrf_ce.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/halrf/halrf_powertracking_ce.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/halrf/halrf_powertracking.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/halrf/halrf_kfree.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/rtl8822b/halhwimg8822b_bb.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/rtl8822b/halhwimg8822b_mac.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/rtl8822b/halhwimg8822b_rf.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/halrf/rtl8822b/halrf_8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/rtl8822b/phydm_hal_api8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/halrf/rtl8822b/halrf_iqk_8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/rtl8822b/phydm_regconfig8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/rtl8822b/phydm_rtl8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/phydm/txbf/haltxbf8822b.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/btc/halbtc8822bwifionly.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/btc/halbtc8822b1ant.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/hal/btc/halbtc8822b2ant.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/platform/platform_ops.o
CC [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/core/rtw_mp.o
LD [M] /var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.o
Building modules, stage 2.
MODPOST 1 modules
ERROR: "__napi_schedule" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "strsep" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "proc_mkdir_data" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "dev_get_by_name" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "napi_disable" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "__cfg80211_alloc_reply_skb" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "__pskb_copy_fclone" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "yield" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "alloc_etherdev_mqs" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "unregister_netdev" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "flush_signals" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "usb_kill_urb" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "proc_create_data" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "find_vpid" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "kernel_sigaction" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "kill_pid" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "cfg80211_connect_done" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "netif_napi_add" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "up" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "register_netdev" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "cfg80211_roamed" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "kthread_should_stop" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "napi_complete_done" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "kthread_create_on_node" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "PDE_DATA" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "complete_and_exit" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "cfg80211_disconnected" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "kthread_stop" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "__tasklet_hi_schedule" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "strpbrk" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "__cfg80211_send_event_skb" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "param_array_ops" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "seq_open" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "down_interruptible" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "proc_get_parent_data" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "kernel_read" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "strrchr" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "filp_close" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "napi_schedule_prep" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "filp_open" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "usb_autopm_get_interface" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "cfg80211_vendor_cmd_reply" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "usb_autopm_put_interface" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "nla_put_nohdr" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "__cfg80211_alloc_event_skb" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
ERROR: "netif_napi_del" [/var/lib/dkms/rtl88x2bu/5.3.1/build/88x2bu.ko] undefined!
make[2]: *** [scripts/Makefile.modpost:91: __modpost] Error 1
make[1]: *** [Makefile:1601: modules] Error 2
make[1]: Leaving directory '/usr/src/linux-headers-5.2.11-amd'
make: *** [Makefile:2011: modules] Error 2

[gnumoksha]

I've successfully compiled this driver under Debian

root@galadriel:/tmp# lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux bullseye/sid
Release:        testing
Codename:       bullseye
root@galadriel:/tmp# uname -a
Linux galadriel 5.3.0-3-amd64 #1 SMP Debian 5.3.15-1 (2019-12-07) x86_64 GNU/Linux
root@galadriel:/tmp# gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/8/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 8.3.0-26' --with-bugurl=file:///usr/share/doc/gcc-8/README.Bugs --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr --with-gcc-major-version-only --program-suffix=-8 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie --with-system-zlib --with-target-system-zlib=auto --enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu --with-build-config=bootstrap-lto --enable-link-mutex
Thread model: posix
gcc version 8.3.0 (Debian 8.3.0-26)

What I've installed: apt install git gcc build-essential bc linux-headers-$(uname -r) dkms