According to the ELF runtime handling of TLS document, the x86-64 arch
uses the same TLS handling variant (GNU) as the IA-32 ABI with the
exception that pointers are 8-byte wide and that the gs register is
swapped with fs. fs:0x0 points to the TCB; TLS variables are located
before it and are accessed using negative offsets from the TCB pointer.
In the Go case the G struct is accessed at fs:-0x8.
For more detauls see: https://www.akkadia.org/drepper/tls.pdf
By setting up pwd as a Go workspace, we can trim import paths from
something like "github.com/achilleasa/gopher-os/kernel" to just
"kernel".
These changes make forking easier and also allows us to move the code to
a different git hosting provider without having to rewrite the imports.
