fix JCPU etc in w.c

find out good gcc macros for all the arch's to make a good #if defined wrapper
about the inline assembly macros in string.h.

fix free.c and xcpustate to use libproc instead of their own meminfo stuff.

extract /proc/stat parsing from vmstat into libproc

fix w.c, top.c to use readproc

Rationalize `ps' option processing and allow a binding for system V like flags
and formats.  Remove PS_* constants, replace with three boolean macros defined
on fmt,CL_fmt for the three places outside of option parsing PS_ are actually
used.  Also, the ps CL args fall into three distinct operation categories:
format flags, verbosity control, process list filters, and sorting specs.  The
man page and code might be clearer if presented in this light.

Add numeric tty option, 'N' to optionally use <maj>,<min> (like ls -l).  Wrap
all p->ttyc refs inside a macro that expands to the right thing.
