vim: use 'noexpandtab'

Since the code uses tabs already, enforce that instead of the opposite.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
unbreak 32-bit builds, support non-x86 platforms

On platforms without RDTSC, we currently just fall back to using libtime_wall()
for any libtime_cpu() calls, and cpu_to_wall is effectively a no-op.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>