sdcc does not build for centos 8 without diving deeper into the
dependency hell:
nothing provides gputils,
nothing provides python3-base,
nothing provides inkscape,
nothing provides lyx,
nothing provides makeinfo
So let's not build libusrp for centos 8 for now. We can build osmo-trx
without the usrp1 backend (already configured in the spec.in file).
Related: OS#4550
Change-Id: Icfb289b0eeeb7215d23517fb8a4e56f2a8d774f1