riscv: remove more riscv64sf support

[brooks]

Summary

Remove a few more bits of riscv64sf support in libc and libm.

Fixes: 1ca12bd927d7 Remove the riscv64sf architecture.

[jrtc27]

lib/msun/riscv/fenv.h

73–76

Don't think we need to spend 10 lines of code to make the errors marginally more friendly. Arguably even this is unnecessary; you'll get an error from the linker if you mix different float ABIs, and crt* are hard float.

[brooks]

Drop __riscv_float_abi_soft in fenv.h

[imp]

I think tis is good... not sure about jrtc's comments

[jhb]

lib/msun/riscv/fenv.h

73–76

Yeah, I would just go with Jess' suggestion here.

[brooks]

lib/msun/riscv/fenv.h

73–76

So delete the whole block?

[jhb]

lib/msun/riscv/fenv.h

73–76

Either that or the suggested code block in Jess's comment that has a single #ifndef around an #error. I don't have a strong preference.

[brooks]

• Squash with D44331
• Reduce ABI checks as suggested