Rune - Fix compile errors/warnings

Rune - Fix compile errors/warnings

on FreeBSD/clang.

Other compile time errors that I didn't go far as to change are
1. cpu_ccfence() which is DragonFly specific function for inline asm
2. *(int*)0 = 1;
3. (StrTable *)(__DECONST(char *, str) - xxx);