not sure if you have any findings.
I compiled lede r6395-6c19407 on ubuntu 32bit 16.04.4 LTS Linux U32 4.14.0-041400-generic, target is x86.
then the image was running on my x86 machine, but tried to run ifconfig, it gave me errror in libc.so:
root@OpenWrt: ifconfig
[ 582.302960] traps: ifconfig[3031] general protection ip:b7fc7dd8 sp:bff405e8 error:0 in libc.so[b7f81000+65000]
Segmentation fault