ensure AutoRemoteSyscalls knows how to perform x86-64 syscalls
only complain about x86-64 images with an i386 host
use target types, not host ones, for remote_ptr in process_execve
compensate for x86-64's slightly different auxv entry ordering
add an arch() method to BaseArch
conditionally use mmap2 when setting up scratch memory
define architecture-specific variants of REGCMP
define x86-64 user_regs_struct more conveniently for GDB
handle differing semantics for the mmap system call
generate specialized per-arch versions of syscallname_arch
ensure that Task's syscallname uses the correct arch
make is_always_emulated_syscall multi-arch aware
define the {,f,l}stat syscalls as emulated syscalls

This is the easiest way to support x86-64's use of these syscalls.
define the arch_prctl syscall for x86-64
fix typo in setrlimit description
define the getrlimit syscall for x86-64
fix base address for x86-64 vdso monkeypatching
define fcntl constants in kernel_abi.h
convert switches to use our defined fcntl constants
add support for the fcntl syscall