The new target is not automatically using PIC.
Need some linker script corrections for errors that were hiding
previously, so that we don't accidentally generate alignment
exceptions on bss size variables that cause the target to fail.
We have a generic target for writing bare-metal code
for 64-bit ARM architectures in upstream Rust now.
Use it to get rid of the fully custom target spec.
\o/
We now have the same API for MMIO and CPU registers.
Makes the code more concise, inntuitive, and improves readability.
https://crates.io/crates/register
In rust-lang/rust@679657b863 a breaking
change was introduced that now requires compiler_builtins. Add them,
and use the opportunity to kick out rlibc, since memset() et al. can
be provided by compiler intrinsics.
Upon further reading, found out that RPi3 features an A53 CPU, which
is one of the ARMv8-A variants that in fact does _not_ have
out-of-order execution.
