yquake2 compiling for riscv boards

[protocultor]

...or, at the very least, it's compiling now on those.
Someone with the hardware might do a better testing of this.

Also included infinite loop fix included in "padnum" patch (yquake2/yquake2#1279).

[dmanlfc]

Separate them out please.
We cannot also assume it will work on riscv unless someone verifies it.
None of the team have the device to test and the horsepower of the device is very weak. I doubt the performance will be acceptable anyway.

[protocultor]

I've separated every fix in different commits.
After reading some benchmarks on the JH7110, which compares it to something between a RPi2 and a 3, I'm no longer worried about performance, especially when some of the boards support GLES3. At worst, using GLES1 will solve possible performance issues.
Reminder that a RPi3 achieves 142 fps average, 102 fps minimum, at 720p with vsync disabled using GLES1.

[dmanlfc]

Separate PRs. We cannot assume it works. Either someone verifies it or we don't add it.

[protocultor]

Outdated comment. The PRs have been separated.

[protocultor]

Now this includes only what's needed to compile on riscv boards, without even removing the if in Config.in. Nothing more.