Linking error riscv64

[jal-frezie]

If I attempt to build a big prolog executable on riscv64 I get an error from the linker:

System/bin/gmain.o: in function .Lcont24139': (.text+0x100222): relocation truncated to fit: R_RISCV_JAL against fail'
collect2: error: ld returned 1 exit status
compilation failed

This appears to be because the "j" instruction jump is limited to +-1MB offset. The code can be made to build OK by setting line 348 of riscv64_any.c to:

if (1)

thus avoiding the use of j altogether.