I've been working with an Archer C7, the patches were originally applied to master but I found that it caused the router to "lock up". I then moved to "lede-17.01" and was able to bring up the two interfaces with my patches up update wpa_supplicant.
Apparently, there are already patches for mesh/AP on a single radio, and it now is sort-of working on builds off lede-17.01 I say "sort of" as when I add an AP into the mix, the logs get filled with endless repetitions of kernel WARNING of the form ... Great, now it's not doing it.
Ugh, needless to say, I'm still debugging this.
Edit: Let me get a couple more build trees up and configure them with all kmods, as I strip out ppp and the like from my builds. I'll get a web server up and public facing as well to support them. @ghoffman - are there any specific packages you need in an Image Builder?
root@test:~# cat /etc/openwrt_release
DISTRIB_ID='LEDE'
DISTRIB_RELEASE='17.01-SNAPSHOT'
DISTRIB_REVISION='r2993+875-b9a408c'
DISTRIB_CODENAME='reboot'
DISTRIB_TARGET='ar71xx/generic'
DISTRIB_ARCH='mips_24kc'
DISTRIB_DESCRIPTION='LEDE Reboot 17.01-SNAPSHOT r2993+875-b9a408c'
DISTRIB_TAINTS='no-all busybox'
root@test:~# opkg list-installed
ath10k-firmware-qca988x - 2017-01-11-ab432c60-1
base-files - 173.5-r2993+875-b9a408c
block-mount - 2018-01-04-37762ff4-1
busybox - 1.25.1-4
ca-bundle - 20170717
diffutils - 3.3-2
dropbear - 2017.75-4
findutils-find - 4.6.0-1
firewall - 2017-05-27-a4d98aea-1
fstools - 2018-01-04-37762ff4-1
fwtool - 1
git - 2.11.0-1
gre - 1-7
hostapd-common - 2018-03-13-c63e69c3-6
ip6tables - 1.4.21-3
iptables - 1.4.21-3
iw - 4.9-1
iwinfo - 2016-09-21-fd9e17be-1
jshn - 2018-01-07-1dafcd78-1
jsonfilter - 2016-07-02-dea067ad-1
kernel - 4.4.120-1-130ff56cb7e319063d074ae916a2ce17
kmod-ath - 4.4.120+2017-01-31-3
kmod-ath10k - 4.4.120+2017-01-31-3
kmod-ath9k - 4.4.120+2017-01-31-3
kmod-ath9k-common - 4.4.120+2017-01-31-3
kmod-cfg80211 - 4.4.120+2017-01-31-3
kmod-crypto-crc32c - 4.4.120-1
kmod-crypto-hash - 4.4.120-1
kmod-fs-ext4 - 4.4.120-1
kmod-gpio-button-hotplug - 4.4.120-2
kmod-gre - 4.4.120-1
kmod-gre6 - 4.4.120-1
kmod-ip6-tunnel - 4.4.120-1
kmod-ip6tables - 4.4.120-1
kmod-ipt-conntrack - 4.4.120-1
kmod-ipt-core - 4.4.120-1
kmod-ipt-nat - 4.4.120-1
kmod-iptunnel - 4.4.120-1
kmod-iptunnel6 - 4.4.120-1
kmod-lib-crc16 - 4.4.120-1
kmod-mac80211 - 4.4.120+2017-01-31-3
kmod-nf-conntrack - 4.4.120-1
kmod-nf-conntrack6 - 4.4.120-1
kmod-nf-ipt - 4.4.120-1
kmod-nf-ipt6 - 4.4.120-1
kmod-nf-nat - 4.4.120-1
kmod-nls-base - 4.4.120-1
kmod-usb-core - 4.4.120-1
kmod-usb-ledtrig-usbport - 4.4.120-1
kmod-usb2 - 4.4.120-1
lede-keyring - 2017-01-20-a50b7529-1
less - 481-1
libblobmsg-json - 2018-01-07-1dafcd78-1
libbz2 - 1.0.6-3
libc - 1.1.16-1
libcares - 1.11.0-1
libffi - 3.2.1-2
libgcc - 5.4.0-1
libip4tc - 1.4.21-3
libip6tc - 1.4.21-3
libiwinfo - 2016-09-21-fd9e17be-1
libiwinfo-lua - 2016-09-21-fd9e17be-1
libjson-c - 0.12.1-1
libjson-script - 2018-01-07-1dafcd78-1
liblua - 5.1.5-1
libmosquitto-ssl - 1.4.15-1
libncurses - 6.0-1
libnl-tiny - 0.1-5
libopenssl - 1.0.2n-1
libpcap - 1.8.1-1
libpthread - 1.1.16-1
librt - 1.1.16-1
libubox - 2018-01-07-1dafcd78-1
libubus - 2017-02-18-34c6e818-1
libubus-lua - 2017-02-18-34c6e818-1
libuci - 2018-01-01-141b64ef-1
libuci-lua - 2018-01-01-141b64ef-1
libuclient - 2017-11-02-4b87d831-1
libustream-openssl - 2016-07-02-ec80adaa-3
libuuid - 2.29.2-1
libxtables - 1.4.21-3
logd - 2017-03-10-16f7e161-1
lua - 5.1.5-1
luci - git-18.061.17832-d092772-1
luci-app-firewall - git-18.061.17832-d092772-1
luci-base - git-18.061.17832-d092772-1
luci-lib-ip - git-18.061.17832-d092772-1
luci-lib-jsonc - git-18.061.17832-d092772-1
luci-lib-nixio - git-18.061.17832-d092772-1
luci-mod-admin-full - git-18.061.17832-d092772-1
luci-proto-ipv6 - git-18.061.17832-d092772-1
luci-proto-ppp - git-18.061.17832-d092772-1
luci-ssl-openssl - git-18.061.17832-d092772-1
luci-theme-bootstrap - git-18.061.17832-d092772-1
mosquitto-client-ssl - 1.4.15-1
mtd - 21
nano - 2.7.5-1
netifd - 2017-01-25-650758b1-1
openssl-util - 1.0.2n-1
opkg - 2017-12-08-9f61f7ac-1
procd - 2018-01-22-9a4036fb-1
resolveip - 2
rpcd - 2017-12-07-cfe1e75c-1
swconfig - 11
tcpdump-mini - 4.9.2-1
terminfo - 6.0-1
uboot-envtools - 2015.10-1
ubox - 2017-03-10-16f7e161-1
ubus - 2017-02-18-34c6e818-1
ubusd - 2017-02-18-34c6e818-1
uci - 2018-01-01-141b64ef-1
uclient-fetch - 2017-11-02-4b87d831-1
uhttpd - 2017-11-04-a235636a-1
uhttpd-mod-ubus - 2017-11-04-a235636a-1
usign - 2015-07-04-ef641914-1
wpad-mesh - 2018-03-13-c63e69c3-6
zlib - 1.2.11-1
root@test:~# cat /etc/config/network
config interface 'loopback'
option ifname 'lo'
option proto 'static'
option ipaddr '127.0.0.1'
option netmask '255.0.0.0'
config globals 'globals'
option ula_prefix 'fdf9:2b1f:8aea::/48'
config interface 'mesh'
option type 'bridge'
option stp '1'
option proto 'static'
option ipaddr '172.16.1.100'
option netmask '255.255.255.0'
config interface 'vlan100'
option type 'bridge'
option stp '1'
option ifname 'eth0.100'
option proto 'static'
option ipaddr '192.168.1.100'
option netmask '255.255.255.0'
option gateway '192.168.1.1'
option dns '192.168.1.1'
#
# Switch Config
#
[...]
root@test:~# cat /etc/config/wireless
config wifi-device 'radio24'
option type 'mac80211'
option channel '6'
option hwmode '11g'
option path 'platform/qca955x_wmac'
option htmode 'HT20'
option require_mode 'g'
option disabled '0'
config wifi-device 'radio5'
option type 'mac80211'
option channel '149'
option hwmode '11a'
option path 'pci0000:01/0000:01:00.0'
option htmode 'VHT80'
option require_mode 'ac'
option disabled '0'
config wifi-iface 'mesh0'
option device 'radio5'
option mode 'mesh'
option mesh_id '<mesh0_id>'
option mesh_fwding '1'
option encryption 'psk2+ccmp'
option key '<mesh0_secret>'
option network 'mesh'
config wifi-iface '5Gap'
option device 'radio5'
option mode 'ap'
option ssid '<5Gap_ssid>'
option encryption 'psk2+ccmp'
option key '<5Gap_secret>'
option network 'vlan100'