`Elf*_Rela` relocations store their argument in `r_addend`, including for `R_*_RELATIVE` relocations. Unlike `Elf*_Rel` relocations, they are not applied as a delta to the destination virtual address. Instead, they are computed from `base_address + r_addend` directly.
Most of this migration was performed automatically with `zig fmt`. There
were a few exceptions which I had to manually fix:
* `@alignCast` and `@addrSpaceCast` cannot be automatically rewritten
* `@truncate`'s fixup is incorrect for vectors
* Test cases are not formatted, and their error locations change
* Don't skip the TLS initialization (Fixes#9083)
* Add a test case where a PIE program is built and run
* Refactor the common initialization code in the Linux startup
sequence.
