@jose-pr i've built and loaded that successfully on my router (Linux lede 4.4.53 #0 Tue Mar 14 12:29:03 2017 mips GNU/Linux) but it has the same issue as stated in the above post (for me).
note: i've also just built and loaded Grawp/rtl8812au_rtl8821au (RTL871X: rtl8812au v4.3.20_16317.20160108) succesfully, same issue as above (for me).
edit: @jose-pr can you provide the build fail messages? otherwise it's hard for someone to help 
edit2: my issue seems to be the same as here: https://github.com/dl12345/rtl8812au/issues/1 and https://github.com/dl12345/rtl8812au/issues/2
Okay, so now going back at it and I got the AP to broadcast with a manual setup via command line (broadcasting with hostapd).
and here we are with client mode (but i need to make route rules. this was connected with wpa_supplicant and udhcpc):
root@lede:~# iw wlan2 link
Connected to xx:xx:xx:xx:xx:xx (on wlan2)
SSID: itsmelol
freq: 2437
signal: -44 dBm
tx bitrate: 72.2 MBit/s
root@lede:~# iwconfig wlan2
wlan2 IEEE 802.11gn ESSID:"itsmelol"
Mode:Managed Frequency:2.437 GHz Access Point: xx:xx:xx:xx:xx:xx
Bit Rate:72.2 Mb/s
RTS thr:off Fragment thr:off
Encryption key:off
Power Management:off
Link Quality=54/100 Signal level=100/100 Noise level=0/100
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
root@lede:~# ifconfig wlan2
wlan2 Link encap:Ethernet HWaddr 11:22:33:44:55:66
inet addr:10.242.242.199 Bcast:10.243.255.255 Mask:255.252.0.0
inet6 addr: fe80::76da:38ff:feaf:b870/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:3148 errors:0 dropped:140 overruns:0 frame:0
TX packets:212 errors:0 dropped:12 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:980 (980.0 B) TX bytes:21111 (20.6 KiB)
edit again: actually i was confused trying to get it routed on net masked 255.252.0.0 network but it's connected just fine on a 255.255.255.0 network with the wpa_supplicant and udhcpc commands. [i need to figure out why it wasn't routed properly on a 255.252.0.0 network but i can't test that right now] but im using it to send this message through my router. pretty happy 
edit again: there wasn't a routing issue before it was a dns issue. which was not handling the dns provided by the hotspot (so that you could login). once i edited /usr/share/udhcpc/default.script to understand $dns i had no issues with that network either